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I tried to sowing roses from rose hips the first time. (In autumn I collected some rose hips random from different bushes in the neighborhood. I mixed the seeds while sowing.) Now the seedlings grow one after another. Thereby I noticed, that some have their first leaves in a more red color, and others in a clear green.
Could I conclude some characteristics of the grown up plant out of this?
(I tried to search for "roses red or green leaves" but only get an amount of results with red petals… )
How to Grow Lenten Rose
Lenten rose (Helleborus x hybridus) is not a rose, but rather a perennial belonging to the buttercup family. As a group, the Helleborus species and hybrids, including Lenten rose, are known as hellebores. The two-part common name of Lenten rose refers to the plant's bloom season (around Lent) and the rose-like shape of its flower buds.
Lenten rose is a hybrid plant, bred from crossing H. orientalis with other closely related species to improve the flowers. Valued for its early blooms of purple, red, yellow, green, blue, lavender, and pink, and its leathery evergreen foliage, the Lenten rose contributes good color throughout the growing season.
The flowers—actually sepals, which are similar to petals but longer-lasting—are large (3 to 4 inches in diameter) and hang downward in clusters from thick stems that rise above the foliage. In addition to the color variations, there may be variations in markings, such as margins of a different color, showy freckling, or veining. Flowering initially occurs near ground level, below last year's leaves.
Lenten rose is normally planted from nursery seedlings which will flower in their first year. Grown from seeds, Lenten rose takes two or three years to mature into a flowering plant. Hellebores can be planted in early fall or late spring and have a long eight- to 10-week bloom period. When they reseed and spread to fill in an area, their attractive foliage makes them a gorgeous ground cover. Lenten rose will also naturalize under the right conditions. But if you wish to keep your Lenten roses as single specimens, well-established seedlings can be transplanted to another part of your garden.
|Botanical Name||Helleborus x hybridus|
|Common Name||Lenten rose|
|Plant Type||Evergreen perennial|
|Mature Size||18–24 inches tall, 18 inches wide|
|Sun Exposure||Part shade|
|Soil Type||Rich, moist, well-draining|
|Flower Color||Purple, red, yellow, green, blue, lavender, or pink|
|Hardiness Zones||4–9 (USDA)|
|Native Area||Southern Europe|
|Toxicity||Toxic to people and animals|
Top 2 Plant Growth Inhibitors: Abscisic Acid and Ethylene
Some plant hormones result in inhibition, rather than stimulation, of growth and development in plants. Although in the past a number of inhibitory substances have been isolated, their true role as naturally occurring growth regulators remained suspect.
However, one growth inhibitor has been unequivocally established as a category of growth substances equal to auxins, gibberellins and cytokinins. This substance is abscisic acid.
Plant Growth Inhibitors # 1. Abscisic Acid (ABA):
The name abscisic acid (ABA) is derived from the ability of this substance to promote abscission, a discovery made by F.D. Addicott et. al. in California (1963) working on the abscission of cotton bolls. ABA has been found in all higher plant tissues these include leaves, roots, xylem of tree trunks, xylem sap, phloem sap, pollen, petals, fruits and seeds (Milborrow, 1974). Concentrations, however, vary widely.
The application of ABA to an actively growing twig of a woody plant results in cessation of elongation of the internodes some of the leaves develop abscission layers and drop off, young developing leaves form scale leaves instead of foliage leaves, and the terminal bud becomes quiescent. Similar response of twigs is normally seen at the onset of the winter season and ABA may be described as a “dormancy-inducing hormone”.
Physiological Roles of ABA:
1. Abscission of leaves and flowers:
Application of ABA causes very fast abscission of leaves and flowers.
ABA accelerates the process of ageing by causing break down of proteins and nucleic acids.
3. Cell division and cell elongation:
ABA also delays cell division and cell elongation.
Interestingly enough, ABA has also been found to promote certain growth processes, such as stimulation of parthenocarpic seed development, rooting of cuttings, elongation of hypocotyls, at very low concentrations.
ABA is known to induce and maintain dormancy in potato tubers and buds, and dormant potato tubers and resting buds contain more ABA than active tubers and buds. Gibberellins and cytokinins are capable of antagonizing the effect of ABA, and break dormancy.
6. ABA as a Stress Hormone:
ABA is generally referred to as “Stress Hormone”, which is a most suitable description of its overall role in the plants. Generally it is formed in response to stress or unfavourable environmental conditions, and it, in turn, changes the plant to withstand that stress. The most striking example of such a response is the rapid synthesis of ABA in response to water stress, that is. a shortage of water.
When a plant is deficient in water, the ABA content of the leaves rises rapidly. This then acts on the guard cells of stomata, “deflating” them so as to close the stomata rapidly, long before such a closure would occur from overall water loss by the plant. Other stresses such as low temperature can also lead to the synthesis of ABA and the closure of stomata.
The change of seasons in temperate zones poses survival problems for plants which are partially overcome by their induction into and release from dormancy. Thus, diminishing day-lengths can induce the formation of ABA that reduces the active vegetative growth of a bud or a developing embryo, and sets in motion the events that lead to winter dormancy. On return of favourable season dormancy is broken by removing the effect of ABA by substances such as cytokinins.
Though ripening fruits contain large amount of ABA, yet application of ABA to fruit has little or no effect. However, as an exception, when ABA is applied to ripening grape berries, their ripening is accelerated and their colour changes fast. ABA in the fruit coat does not affect the germination or dormancy of seed. ABA is present in fairly constant amounts throughout the development of seed. However, the aborted fruits contain larger amounts of ABA.
ABA is known to rarely induce parthenocarpic development of fruits in some plants (e.g. in emasculated fruits of Rosa sherardii, the wild rose, as reported by Jackson & Blundell, 1966).
ABA does not ordinarily promote growth of flowers in short-day plants. High concentrations of ABA usually inhibit or delay flowering in plants. Both ABA and ethylene appear to act in part through effects on differentially permeable membranes and in part through control of protein synthesis.
Applications of Abscisic Acid:
Application of small quantities of ABA to the leaves reduces the rate of transpiration in a plant by inducing closer of a stomata. This way a lot of water can be conserved by the crop.
It is also used in inducing flowering in short day plants, rooting of stem cuttings in some plants, and for inducing dormancy in buds and seeds.
Plant Growth Inhibitors # 2. Ethylene:
It has been known for many years that over ripe fruits produce something that hastens ripening of adjacent fruits (“one rotten apple will spoil a barrel”). This fruit ripening factor has proved to be the simple unsaturated hydrocarbon, ethylene (C2H4). It is synthesized from amino acid methionine. It is component of manufactured coal gas and was identified by the hastening of ripening of fruits exposed to accidental leakages of coal gas.
Ethylene is a natural plant product which is produced by ripe fruits and acts like a plant hormone. Ripe fruits produce ethylene which stimulates ripening of adjacent fruits (and the production of ethylene by them). Fruits such as bananas that are picked green for transport to market are treated with ethylene so that they will be properly ripe when they reach the market.
Premature ripening of fruit in a warehouse can be prevented by ventilation to remove the ethylene and by increasing the content of carbon dioxide in the air, for carbon dioxide counters the effect of ethylene.
Ethylene is a rather different type of hormone from the four previous categories in that it is a gas. It is released from most plant organs in varying concentrations, most obviously from ripening fruits. In trace amounts it interacts with the other plant hormones, especially auxin, to coordinate and regulate a wide variety of growth and developmental processes.
Effects of ethylene are very striking in case of fruit ripening, abscission, breaking of dormancy, flowering, and modification of sex expression. Ethylene as a plant hormone is unique in its structural simplicity and gaseous nature.
The Russian botanist Neljubow (1901) is believed to have been the first to recognize the growth-regulatory properties of ethylene. By 1930 ethylene was recognized to have a wide variety of interesting effects on plants. Gane in 1934 discovered that ethylene was a natural plant product. Soon after, Crocker, Hitchcock & Zimmerman in 1935 reported that ethylene is a fruit-ripening hormone and it also acts as a regulator in vegetative plant organs.
By 1960 ethylene had been clearly identified as an endogenous regulator of fruit-ripening. In-rolling of petals in opened flowers (i.e., sleep disease) is caused by ethylene. Even 1 ppm of ethylene prevents opening of flower bud.
Physiological Roles & Uses of Ethylene:
Fruit ripening was the first plant response which was clearly shown to be regulated by ethylene. It has now been fully established experimentally that ethylene is a fruit ripening hormone.
(ii) In seedling growth:
Ethylene acts as a regulator of cell shape and seedling behaviour rather than strictly as growth inhibitor.
There is sufficient experimental evidence available to indicate that ethylene is involved in the abscission (i.e., separation of organs from the plant) of flower bud, flower and young fruit as well as fruit dehiscence. Plant leaves make ethylene which results in their own abscission.
Application of ethylene to leaves triggers a new set of metabolic events leading to abscission these include new cell divisions, forming an abscission layer of weak-walled cells, whose digestion by newly formed cellulose brings about leaf fall.
(iv) Ethylene in normal growth and development:
Ethylene participate in almost all phases of plant growth and behaviour. Ethylene regulates a variety of life processes in plants ranging from release of seed dormancy and early seedling behaviour to leaf abscission and fruit ripening. Ethylene may modify development even when its production rate in the plant is at a very low level.
Commercial Importance of Ethylene:
Ethylene has been commercially exploited in a very big way all over the world for improving the quality or promoting ripening of fruits such as tomatoes, apples, coffee berries and grapes to facilitate harvesting of cherries, walnuts and cotton by accelerating abscission or fruit dehiscence increasing rubber production by prolonging latex flow in rubber trees increasing sugar production in sugarcane synchronizing flowering in pineapple and accelerating senescence of tobacco leaves. For all such purposes ‘liquid-ethylene’ (ethephon), sold in market under the trade name of Ethrel, which is 2-chloroethyl-phosphonic acid (CICH2 CH2 PO3 H2), is used.
Growth and development in any plant is controlled by a group of growth promoters as well as growth inhibitors. The hormones coordinate with each other to bring about growth and differentiation.
Plant morphology and biomass accumulation under different light treatments
A visual overview of the influence of monochromic and mixed R and B light on morphology of sweet pepper seedlings at 28 day (d) after treatment (DAT) was shown in Fig. 1 and Supplementary Fig. 2 and the differences among different treatments were significant. The plant shoot dry weight (DW) under RB was significantly increased compared with W (P < 0.05), and it was also higher than that under other treatments, whereas, R light produced the lowest DWs (Fig. 2a). The root DWs showed similar trends under all the treatments (Fig. 2b).
Effects of different light treatments on plant morphology of sweet pepper seedlings at 28 day after treatment. W, white light R, monochromatic R light B, monochromatic B light RB, mixed R and B light of 3:1
Effects of different light treatments on (a) shoot dry weight and (b) root dry weight of sweet pepper seedlings at 28 day after treatment. Data are presented as means ± SE, n = 3. Different letters indicate significant differences between values (p < 0.05). W, white light R, monochromatic R light B, monochromatic B light RB, mixed R and B light of 3:1
Leaf anatomy under different light treatments
Table 1 and Fig. 3 showed that R and B light had a significant effect on the anatomical structure of pepper leaves. Leaf thickness was the highest under RB, followed by B and W, while the thinnest leaves were found under R light. Furthermore, compared to W, the thickness of palisade mesophyll tissue (PT), spongy mesophyll tissue (SPT) and the upper epidermis were significantly greater under RB treatment (P < 0.05). These three parameters increased by 26, 19 and 22%, respectively, but they were significantly reduced by R light. Thinner lower epidermal thicknesses were found under R, whereas the epidermis tended to be thicker under RB although they were not significantly different from W. The effect on the PT and SPT ratio was not strong (P > 0.05) and the thinnest cell layers occurred under R.
Effects of different light treatments: (a) white light (b) monochromatic R light (c) monochromatic B light (d) mixed R and B light of 3:1 on leaf sectioning anatomy of sweet pepper seedlings at 28 day after treatment. Images of leaf sectioning anatomy are at the same magnification. The images were taken at 200 × magnification. EP, epidermis cell PT, palisade mesophyll tissue SPT, spongy mesophyll tissue
Photosynthetic light- and CO2-response curves under different light treatments
Both of the net photosynthetic rate (Pn) of the leaves increased rapidly along with the increment in PPFD (Fig. 4a) and CO2 concentration (Fig. 4b) at the initial stage, after that, their increasing tendency gradually became stable. The highest Pn-PPFD response curve value was detected under RB, followed by B and W, whereas R produced the lowest value. Furthermore, different light treatments produced similar trends for Pn-CO2. The apparent quantum efficiency (AQY), light saturation point (LSP), light-saturated maximum (Pnmax), carboxylation efficiency (CE) and CO2 saturation point (CSP) levels and the maximum RuBP regeneration rate were significantly higher under RB (P < 0.05) than those under W, whereas, the light compensation point (LCP) and CO2 compensation point (CCP) values were decreased under this treatment (Table 2 and Table 3).
Effects of different light treatments on (a) photosynthetic light- and (b) CO2-response curves of sweet pepper seedlings at 28 day after treatment. Pn, net photosynthetic rate PPFD, photosynthetic photon flux density W, white light R, monochromatic R light B, monochromatic B light RB, mixed R and B light of 3:1. □ W ● R △ B ◆ RB
Chlorophyll a fluorescence and the chlorophyll fluorescence transients under different light treatments
The effects of R and B light on the pepper seedling Chl fluorescence parameters were shown in Fig. 5. Fv/Fm, which represents the greatest light conversion efficiency or the maximum quantum yield of PS II, was significantly higher under RB and B than that under W and there were no significant differences between RB and B treatments (Fig. 5a). Furthermore, this parameter significantly declined under R (P < 0.05). ΦPSII represents the actual conversion efficiency of PS II or the actual quantum yield and it showed a similar reaction to the four light quality treatments (Fig. 5b). F’v/F’m indicates how efficiency the excitation energy is captured by open photosystem II (PSII) reaction centers and it was enhanced in RB-grown seedlings, followed by W and B, and there were no significant differences among these three treatments (P > 0.05) (Fig. 5c). However, seedlings grown under R light had significantly lower F’v/F’m values (P < 0.05), and no significant difference was found between R and B treatments.
Effects of different light treatments on chlorophyll fluorescence parameters: (a) Fv/Fm, maximum photochemical efficiency of PSII (b) ΦPSII, actual PSII photochemical efficiency (c) F’v/F’m, maximum photochemical efficiency of PSII under light adaptation of sweet pepper seedlings at 28 day after treatment. Data are presented as means ± SE, n = 3. Different letters indicate significant differences between values (p < 0.05). W, white light R, monochromatic R light B, monochromatic B light RB, mixed R and B light of 3:1
The typical polyphasic Chl a fluorescence transient (OJIP) increased at different experimental time points were shown in Fig. 6a-d. In general, the results indicated that the W, B and RB treatments decreased the amplitude of the OJIP curves compared with R, mainly at the J and I step, whereas they were higher under R light. There was no obvious difference in the maximal amplitude of the O and P steps among the treatments (P > 0.05). In order to further study the mechanisms behind the observed changes, the JIP-test was used for the fluorescence induction transients (Fig. 7a-h). Most JIP-test parameters (e.g., the general electron carrier of the reaction center (Sm), the potential for energy conservation from photons absorbed by PSII to the reduction of the intersystem electron acceptors (PIABS), the potential for energy conservation from photons absorbed by PSII to the reduction of PSI end acceptors (PItotal), the quantum yield for reduction of end electron acceptors at the PSI acceptor side (ΦRo) and the efficiency/probability with which an electron from the intersystem electron carriers is transferred to reduce end electron acceptors at the PSI acceptor side (δRo)) were significantly elevated by B and RB compared with W (P < 0.05), but the R light produced relatively lower values. Additionally, the fraction of PSII Chl a molecules that function as reaction centers (RC/ABS), the dissipated energy in the reaction center (DIo/RC) and the maximum trapped energy exciton per active PSII reaction center (TRo/RC) in the leaves under R were significantly greater than those under other treatments (P < 0.05).
Effects of different light treatments on chlorophyll a fluorescence transient (OJIP) of sweet pepper seedlings at different experimental periods. (a), (b), (c), and (d) were at 7, 14, 21, and 28 day after treatment, respectively. W, white light R, monochromatic R light B, monochromatic B light RB, mixed R and B light of 3:1
Effects of different light treatments on JIP-test parameters: (a) RC/ABS, fraction of PSII Chl a molecules that function as reaction centers (b) Sm, general electronic carrier of the reaction center (c) DIo/RC, dissipated energy in the reaction center (d) TRo/RC, maximum trapped energy exciton per active PSII reaction center (e) PIABS, potential for energy conservation from photons absorbed by PSII to the reduction of the intersystem electron acceptors (f) PItotal, potential for energy conservation from photons absorbed by PSII to the reduction of PSI end acceptors (g) ΦRo, quantum yield for reduction of end electron acceptors at the PSI acceptor side (h) δRo, efficiency/probability with which an electron from the intersystem electron carriers is transferred to reduce end electron acceptors at the PSI acceptor side of sweet pepper seedlings at different experimental periods. Data are presented as means ± SE, n = 3. Different letters indicate significant differences between values (p < 0.05). W, white light R, monochromatic R light B, monochromatic B light RB, mixed R and B light of 3:1. □ W ● R △ B ◆ RB
Calvin cycle enzymes activity under different light treatments
Rubisco, FBPase, fructose-1, 6-bisphosphate aldolase (FBA), glyceraldehyde-phosphate dehydrogenase (GAPDH) and transketolase (TK) are key enzymes in the Calvin cycle. The results showed that the Rubisco activities increased initially and then decreased with the duration of different light quality treatments increased (Fig. 8a-e). Seedlings under B and RB had significantly higher Rubisco activities than W-grown seedlings (P < 0.05) with 65 and 36% increases, respectively, at 28 DAT (Fig. 8). In contrast, R-grown plants had a significantly lower activity levels (15% less) than W-grown plants.
Effects of different light treatments on activities of Calvin cycle-related enzymes: (a) Rubisco, ribulose-1, 5-bisphosphate carboxylase/oxygenase (b) FBPase, fructose-1, 6-bisphosphatase (c) FBA, fructose-1, 6-bisphosphate aldolase (d) GAPDH, glyceraldehyde-phosphate dehydrogenase (e) TK, transketolase from sweet pepper seedlings at different experimental periods. Data are presented as means ± SE, n = 3. Different letters indicate significant differences between values (p < 0.05). FW, fresh weight W, white light R, monochromatic R light B, monochromatic B light RB, mixed R and B light of 3:1. □ W ● R △ B ◆ RB
Sharp increases in FBPase activity were observed in pepper seedlings under the different light treatments. The FBPase activities reached their highest levels at 21 DAT and then decreased over the following days (Fig. 8b). Activities of this enzyme in plants under B light remained significantly higher than those under other treatments from 7 to 21 DAT (P < 0.05), but there was no significant difference between W and B at 28 DAT (P > 0.05). Significantly lower activities were observed under R light than those under other treatments during the experimental period. The FBA activities in plants treated with W and R light increased slowly during the experimental period (Fig. 8c), whereas, they rapidly increased in the RB and B treatments after 14 DAT, which indicated that the enzyme activity in the RB and B treatments was greater than in the W and R treatments. The GAPDH activities decreased in plants under all treatments, but the W and RB light applications alleviated the reduction (Fig. 8d). The TK activities were similar under all the treatments during the experimental period, except that the GAPDH and TK activities were significantly lower under the R-treatment than those under other treatments (Fig. 8e).
Gene expression under different light treatments
The RT-PCR method was used to analyze the relative expression levels of FBA, FBPase, GAPDH and TK genes involved in the Calvin cycle after pepper seedling exposure to different light qualities for 28 d. Figure 9a-d showed that the transcriptional levels of these genes varied significantly depending on the light qualities supplied and similar variation patterns were obtained for FBA, FBPase and GAPDH under different treatments. Generally, compared to W, seedlings under RB showed significantly increased expression levels of these three genes, whereas exposure to R light resulted in decreased gene transcription. Additionally, the relative expression level of TK was up-regulated in B-treated seedlings, followed by RB and W, but R produced the lowest TK levels.
Effects of different light treatments on expression of (a) FBA (b) FBPase (c) GAPDH (d) TK from sweet pepper seedlings at 28 day after treatment. Data are presented as means ± SE, n = 3. Different letters indicate significant differences between values (p < 0.05). W, white light R, monochromatic R light B, monochromatic B light RB, mixed R and B light of 3:1
The Leaf: Meaning, Types and Modification
The leaves are the most conspicuous vegetative organs of the plants. They are lateral dissimilar outgrowths or appendages of the stems or branches. Leaves are usually green, flat, expanded organs of limited growth. They develop from the nodes having invariably buds at their axils, and remain arranged in acropetal order.
Leaves originate as exogenous outgrowths from the grow­ing point of the stem. These protuberances are called leaf primordia, which, by continued growth, develop into the mature green leaves called foliage leaves.
Functions of the Leaf:
Leaves are of paramount importance as they are mainly res­ponsible for the manufacture of food. Photosynthesis, as the process is called, is the main function of the leaf. Owing to the presence of chlorophyll, the green colouring pigment, the leaves can manu­facture complex organic food matters (like sugar and starch), out of water and carbon dioxide gas absorbed from the soil and air respectively, with the aid of sunlight.
Leaves also carry on respira­tion, an energy releasing process, which involves intake of oxygen and outgo of almost equal volume of carbon dioxide. All living organs, of course, have this function. The third function of the leaf is transpiration or giving out of excess of water as water vapour.
Plants usually absorb water from the soil much in excess of their need. They get rid of the surplus water by transpiration. Besides these normal functions, leaves protect the axillary buds, often store up water and food matters and perform other special functions as well.
Parts of a Typical Leaf (Fig. 61):
A typical or an ideal leaf has usually three parts:
(i) Leaf base, by means of which the leaf remains attached to the stem or branch.
(ii) Leaf stalk or petiole, the cylindrical stalk which con­nects the leaf base with the flat blade.
(iii) Leaf blade or lamina, the green flat expanded part of the leaf. It goes without saying that the blade is the most impor­tant part.
The blade has usually a prominent rib running up to the tip. It is the midrib. The midrib has many branches and sub- branches distributed in the lamina. They are called veins. Veins really form the skeleton of the leaf on which softer materials remain inserted, and they are the channels for conduction of water and food. The outer edge of the leaf forms the margin, and the extreme tip, the apex.
Simple and Compound Leaves:
A leaf is called simple when it has a single blade with entire or incised margin. It is simple so long it presents a single appearance. According to the degrees of incisions, the suffixes ‘fid’, ‘partite’ and ‘sect’ are used.
A simple leaf with pinnate or uni­costate. Venation is called pinnatifid, when it has incisions less than halfway towards the midrib, as in Chrysanthemum (B. Chandramallika) it is pinnati-partite, if the incisions extend beyond halfway, e.g. Argemone (B. Shialkanta) and it is pinnati-sect, when the incisions almost reach the midrib, as in marigold, Ipomoea (B. Tarulata).
Similarly simple leaves with multicostate or palmate venation may be palmate-fid, e.g. lady’s finger palmati- partite, e.g. bitter gourd (B. Uchche) and palmati-sect, as in morning glory (Fig. 70).
But when the incisions reach the midrib, breaking down the leaf into a number of segments or leaflets, the leaf is called compound.
The leaflets of a com­pound leaf may remain attached to a common axis, called rachis, like the pinnae of a feather or may be jointed or articulated to a common point on an axis like the outstretched palm. The former types are called pinnate compound leaves and the latter are known as palmate compound leaves.
Pinnate Compound Leaves (Fig. 71):
The leaflets of a pinnate compound leaf remain attached to an axis called rachis. If they are arranged in pairs, the rachis ends abruptly and the number is even, the leaf is called pari-pinnate as in tamarind, Cassia (B. Kalkasunde), but if a terminal leaflet is present on the rachis, naturally making the number odd, the leaf is called imparipinnate, as in rose, Clitoria (B. Aparajita).
Pinnate compound leaves may be unipinnate or once pinnate, bi-pinnate or twice pinnate, tri-pinnate or thrice pinnate, and so on.
Paripinnate leaves of tamarind and impari­pinnate leaves of roses are unipinnate, as they have leaflets attached directly to the rachis. In bi-pinnate leaves the rachis is branched and the leaflets are arranged pinnately on the secondary axes of the rachis, as in the sensitive plant (B. Lajjabati).
The tri-pinnate leaves have the third series of branches bearing leaflets, e.g. horse­radish. When the leaves are pinnate more than thrice they are called decompound, e.g. carrot.
Palmately Compound Leaves (Fig. 72):
Here the leaflets are jointed or articulated to a common point on the axis.
According to the number of leaflets present, palmate compound leaves may be:
(i) Uni-foliate, with only one leaflet, as in lemon
(ii) Bi-foliate, with two leaflets, e.g. Balanites (B. Hinghan)
(iii) Trifoliate, with three leaflets, as in wood apple, Oxalis (B. Amrul)
(iv) Quadrifoliate with four leaflets, as in Marsilea (B. Sushni) and
(v) Digitate, with five or more leaflets, as in silk- cotton.
Differences between a Pinnate Compound Leaf and a Short Branch:
A pinnately compound leaf with many leaflets often closely resembles a branch with simple leaves.
The following characters would show the difference between the two:
(1) A compound leaf has no terminal bud which the branch always has.
(2) A compound leaf develops from the node of the stem or the branch, bearing buds at their axils whereas the short branch is axillary in position.
(3) If stipules are present they are found at the base of the rachis of a compound leaf whereas in a short branch the indivi­dual leaves bear the stipules.
(4) Buds are never present at the axils of the leaflets of a com­pound leaf, but the simple leaves of a short branch invariably bear buds at the axils.
Phyllotaxy of Leaves:
The leaves are not haphazardly arranged on the stems and branches but they come out in a definite order. This arrangement of leaves on the stems and branches is known as phyllotaxy, meaning leaf order. The main object of phyllotaxy is to expose the leaves to proper illumination for different vital functions, avoiding shading as far as possible.
There are three principal types of arrangement (Fig. 73):
(1) Alternate, when a single leaf arises from a node and naturally the leaves are alternately placed. This arrangement is also called spiral, because if an imaginary line is passed through the bases of the leaves in the order of their development, it would form a spiral round the stem.
(2) Opposite, when two leaves develop from a node opposite to each other.
Opposite arrangement may be:
(i) Superposed, when one pair of leaves stands just above the lower pair. Here leaves are arranged in two vertical rows and the internodes are long to avoid shading as far as possible, e.g. guava, Rangoon creeper and
(ii) Decussate, when one pair of leaves is at right angles to the next upper or lower pair, forming four vertical rows of leaves on the stem or branch, e.g. Ocimum (B. Tulsi), Ixora (B. Rangan), Calotropis (B. Akanda).
(3) Whorled or Verticillate, when more than two leaves arise from a node forming a whorl, e.g. Nerium (B. Karabi), Alstonia (B. Chatim).
Plants growing in shady places with poor light exhibit a peculiar sort of arrangement of leaves. Here all the leaves come up and arrange them­selves side by side with a view to utilizing the maxi­mum amount of light. They form something like a mosaic (Fig. 74), hence called leaf mosaic, e.g. Oxalis (B. Amrul), Garden Nasturtium.
Leaves of different forms are sometimes found on the same plant. This condition is known as heterophylly (heteros=different phylla=leaves). Hetero­phylly is particularly noticed in aquatic plants.
Sagittaria or arrow-head, a common water-plant, has two kinds of leaves the submerged ones are ribbon- shaped, whereas the aerial ones are sagittate (arrow-shaped). Many other aquatic plants bear finely dissected submerged leaves and flat expanded floating or aerial leaves.
Heterophyllous condition in aquatic plants is an adaptation to two different environmental conditions. Even land plants often bear different environmental conditions. Even land plants often bears different types of leaves.
Leaves vary considerably in shape in plants like Pterospermun (B. Kanak champa), Artocarpus chaplasa (B. Chaplas), coriander, etc. The first formed leaves in wood apple, Mormodica (B. Uchche), etc., are quite different from later-formed ones.
Kinds of Leaves:
Besides the green foliage leaves, there are other types of leaves as well. Cotyledons of the embryo are the seed leaves, and so are the first leaves of the plants.
The scale leaves, as found in modified stems, are small mem­branous bodies. Bracts are specialised leaves often brightly coloured, bearing floral buds at the axils. The beautifully coloured petals and other floral parts are also specialised leaves meant for reproduction.
Modifications of Leaves:
Leaves are often modified for parrying on special functions.
An account of the modified leaves is given below:
The whole leaf or more commonly the parts of the leaves are modified into slender sensitive tendrils for climbing. The whole lamina in Lathyrus or wild pea, the terminal leaflets in pea, the apex in Gloriosa (B. Ulat chandal), the petiole in Clematis and the stipules in Smilax (B. Kumarika) are modified into tendrils.
The lamina or a part of it may be modified into hard sharp-pointed structure, called spine, for the purpose of self-defence. In common Opuntia (B. Fani manasha) the stem becomes green and flattened (phylloclade) and the leaves are converted into spines.
Similarly the apex of date-palm, the margin of Argemone (B. Shialkanta), stipules in Acacia (B. Babla) is modified into spines. (It should be noted that thorns and spines carry on the same function but thorns are modified stems and spines are modi­fied leaves. The curved sharp-pointed outgrowths of roses are the prickles.)
Many leaves become fleshy and succulent due to the storage of water and food. Here the leaves are partly modified. Leaves of Agave, Aloe, Portulaca (B. Nune-shak), the scaly leaves of onion are familiar examples.
4. Insect-Catching Leaves:
The insectivorous plants have peculiar leaves nicely adapted for catching insects (Fig. 176).
(a) Nepenthes or Pitcher Plant:
Here the leaf-base is modified into a flat lamina-like body, the petiole into a slender coiled tendril for climbing and the lamina into the pitcher proper. The pitcher has a coloured hood for attracting the insects.
(b) Utricularia or Bladder-Wort:
The bladder-worts (B. Jhanji) have much dissected compound leaves. Some of the leaflets are modified into bladders having special devices for catch­ing insects. Each bladder has a valve-like door which opens only inwards. The small aquatic insects push in the valve and are caught. In course of time they die and the bodies are digested.
It is another insectivorous plant where the spatula-shaped leaves bear many tentacles, the tips of which glisten in the sun and look like dew drops. Small insects are attracted, come and rest on the leaf only to find the tentacles bend and imprison them. By the secretion of enzymes the insect body is decomposed. After completing digestion the tentacles resume their original position and get ready for another prey.
5. Leaves of Bryophyllum (B. Pathar kuchi), Begonia bear epiphyllous buds and thus help in vegetative multiplication.
Rosa carolina Rosa carolina, commonly called pasture rose, occurs in both dryish and wet soils. It is typically found in glades, open woods, prairies, along roads and railroads, and in wet soils along streams and swamps and low areas. Grows from 3-5' tall (less frequently to 6') and often spreads by suckers to form colonies or thickets in the wild. Features single (5-petaled), pink flowers (to 2.5" across) which bloom in May. No repeat bloom. It has smooth, dark green foliage. Has red hips in late summer. Best grown in average, medium to wet, well-drained soil in full sun. Best flowering and disease resistance occur in full sun. Water deeply and regularly (mornings are best). Avoid overhead watering. Good air circulation promotes vigorous and healthy growth and helps control foliar diseases. Summer mulch helps retain moisture and keep roots cool. Remove and destroy diseased leaves from plants (as practicable), and clean up and destroy dead leaves from the ground around the plants both during the growing season and as part of a thorough clean-up during winter (dormant season). Crowns appreciate protection in cold winter climates. Prune in late winter to early spring. Seasons of Interest: Blooms: Spring, summer Nut/Fruit/Seed: Fall Remove the white, bitter base of the petals of the edible flowers before using to garnish desserts, freeze in ice cubes and float in punch. The petals can be used in syrup, jelly, butter, and spreads. VIDEO Created by Elizabeth Meyer for "Trees, Shrubs and Conifers" a plant identification course offered in partnership with Longwood Gardens. Charles Wohlers CC BY-NC-ND 4.0 Fritz Flohr Reynolds CC BY-NC 4.0 Malcolm Manners CC BY 4.0 Let's Stay Connected.
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Difference in rose seedlings with red or green seed leaves - Biology
Plants of the Mallow Family
If you have seen a hollyhock or hibiscus flower, then you can recognize the Mallow family. Wild species may be smaller, but you will know you have a Mallow when you find a funnel-shaped flower with 5 separate petals and a distinctive column of stamens surrounding the pistil. There are also 3-5 partially united sepals, often surrounded by several bracts. Crush any part of the plant and rub it between your fingers. You will notice a mucilaginous (slimy) texture, even in seemingly dry, desert species.
Worldwide there are about 85 genera and 1500 species, including 27 genera in North America. Hollyhock, hibiscus, and cotton are members of this family. Cotton is the only member of this family with documented poisonous properties. All others seem to be safe for edible and medicinal uses. Okra is the edible fruit of a variety of hibiscus. Marshmallow was originally derived from the marshmallow plant shown here. Some additional members of the family can be used as marshmallow substitutes. The ground up root or seeds are covered with water and boiled until half the liquid is gone. Then the liquid is beaten to a froth and sugar is added. It should make something resembling whipped cream.
The plants contain natural gums called mucilage, pectin, and asparagin, which gives them a slimy texture when crushed. It is the presence of these gums that creates the marshmallow effect. The members of the Mallow family are mostly edible as a salad greens and potherbs, although not very commonly used, probably due to their slimy consistency. The flowers and seeds are also edible.
Medicinally, the mucilaginous quality of the Mallows may be used just like the unrelated Aloe vera or cactus: externally as an emollient for soothing sunburns and other inflamed skin conditions, or internally as a demulcent and expectorant for soothing sore throats.
Key Words: Key Words: 5 separate petals and a column of stamens. Mucilaginous texture.
Please e-mail Thomas J. Elpel to report mistakes or to inquire about purchasing high resolution photos of these plants.
Key to Genera in the Rocky Mountains
Read through the options and pick the closest match(es).
No bracts (modified leaves) beneath flowers.
Flowers cream-colored. Fruit is a capsule. Hibiscus trionum
Flowers yellow. Fruit forms a ring of seeds. Abutilon theophrasti
One to several bracts beneath flowers. Fruit forms a ring of seeds.
Plants 3-6 feet tall. Palmate, rounded leaves: Alcea
Plants 3-5 feet tall. Palmate, pointed leaves: Iliamna
Plants usually less than 3 feet tall. Mostly rounded leaves. Petal-ends notched: Malva
Plants less than 3 feet tall. Mostly rounded leaves. Flowers whitish. Petal-ends not notched: Sida
Plants less than 3 feet tall. Often deeply divided palmate leaves. Flowers orange: Sphaeralcea
Plants less than 3 feet tall. Deeply divided palmate leaves. Flowers white to pink, red, or lavender: Sidalcea
Plants less than 3 feet tall. leaves 3-5 parted. Hairy. Flowers reddish-purple: Callirhoe involucrata
Tall Mallow: Malva sylvestris. Tall mallow is native to Europe, Asia, and northwestern Africa, but widely naturalized across the English-speaking world. Photographed in New Zealand.
Non-endospermic seed structure (Eudicots): Fabaceae - pea as model system in seed biology
Drawing of a mature pea (Pisum sativum) seed, a typical non-endospermic seed with storage cotyledons and the testa as sole covering letters. Color drawing published in Finch-Savage and Leubner-Metzger (2006).
See the web page"Plant hormones" for information about ethylene and pea seed germination and seedling radicle growth.
There are probably no counties in Missouri where multiflora rose cannot be found today. The species was designated a noxious weed by Missouri state law in 1983. As such, Missouri counties may adopt a law that requires mandatory control of multiflora rose.
Pulling, grubbing, or removing individual plants from the soil is effective only when all roots are removed or when plants that develop afterward from severed roots are destroyed. These approaches are most practical for light, scattered infestations.
In fire-adapted communities, a routine prescribed burn program will hinder invasion and establishment of multiflora rose.
Three to six cuttings or mowings per growing season for more than one year can achieve high plant mortality. Such treatment may need to be repeated for two to four years. Increased mowing rates (more than six per season) did not increase plant mortality.
In high quality communities, repeated cutting is preferred over mowing, because repeated mowing will damage native vegetation as well as multiflora rose.
Cutting then Applying Herbicides
Cutting stems and either painting herbicide on the stump with a sponge applicator (sponge-type paint applicators can be used) or spraying herbicide on the stump with a low pressure hand-held sprayer kills root systems and prevents re-sprouting. With this technique, herbicide is applied specifically to the target plant, reducing the possibilities of damaging nearby, desirable vegetation.
Roundup herbicide (a formulation of glyphosate) has been effective in controlling multiflora rose when used as a 10- to 20-percent solution and applied directly to the cut stump. Although the Roundup label recommends a higher concentration for cut-stump treatment (50- to 100-percent), this lower concentration has proven effective.
Cut-stump treatment is effective late in the growing season (July–Sept), and also during the dormant season. Dormant season application is preferred because it will minimize potential harm to non-target species.
Glyphosate is a nonselective herbicide, so care should be taken to avoid contacting non-target species. Both glyphosate and picloram (Tordon RTU) are recommended for controlling established plants. (Note: some products containing glyphosate or another herbicide may be pre-diluted, so be sure to read product labels to understand herbicide concentration levels).
In addition, Triclopyr (trade name Garlon 3A) can be applied to cut stems or canes for selective control of multiflora rose. Garlon 3A diluted in water at a rate of 50 percent can be sprayed, using a hand sprayer, to the cut surface. Application should be within minutes of cutting.
Use of Garlon 3A is best done in the dormant season to lessen damage to non-target species. Great care should be exercised to avoid getting any of the herbicide on the ground near the target plant since some non-target species may be harmed. Avoid using Triclopyr if rain is forecast for the following one to four days otherwise runoff will harm non-target species.
By law, herbicides may only be applied according to label directions.
Repeated cutting, as discussed above, is effective. For large populations on severely disturbed areas, mowing can be substituted for cutting individual plants. However, mowing multiflora rose can result quickly in flat tires. On mowers, filling tires with foam is recommended.
Fosamine (trade name Krenite) can be applied as a foliar spray in a 2-percent solution plus 0.25-percent surfactant (2 1/2 ounces of Krenite plus 1/2 ounce surfactant per gallon of water). The Krenite S formulation contains the appropriate amount of surfactant. Coverage of foliage should be complete. Krenite should be applied only in July through September. No effects will be observed during the autumn season following application. Slight regrowth may occur the following season but canes will die during the summer. Fosamine kills only woody species and is non-volatile, therefore it is the preferred foliar spray treatment.
Dicamba (trade name Banvel) is an effective foliar spray that is less preferred than Krenite. Banvel is selective against broadleaf plants, so care must be taken to avoid contacting desirable, broadleaf vegetation. It can be applied as a foliar spray in a 1-percent solution (1 ounce of Banvel per gallon of water). Though this solution can be applied any time during the growing season, best results are obtained during May and June when plants are actively growing and flowering, following full leaf-out.
One-half ounce of a surfactant (wetting agent that results in better coverage of the plant) should be added when treating dense foliage and, to enhance control in late season applications, complete coverage of all green leaves should be achieved.
CAUTION! Do not spray Krenite or Dicamba so heavily that herbicide drips off the target species. Foliar spray of herbicides should only be used in less sensitive areas because of problems with contacting non-target species.
Glyphosate (trade name Roundup) is an effective foliar spray when applied as a 1-percent solution to multiflora rose plants that are flowering or in bud. Roundup, however, is not a preferred chemical treatment because it is nonselective and the selective herbicides mentioned above are an effective alternative. Nevertheless, Roundup can be used as a foliar spray during the growing season on severely disturbed sites if care is taken to avoid contacting non-target plants.
Roundup should not be used as a foliar spray during the growing season in high-quality natural communities because it can be result in damage to non-target species. Roundup is useful as a foliar spray for exotic plants that remain green and retain their leaves after native vegetation is dormant or senescent. Multiflora rose does not fit this description adequately and is controlled most effectively when treating during the growing season.