Leaf Growth Stage Research Articles

Sorption of Ozone by ‘New Yorker’ tomato leaves

Tomato ( Lycopersicon esculentum Mill.) ‘New Yorker’ plants were exposed to O 3 to compare leaf diffusive conductance (LDC) before exposure to O 3 with O 3 sorption rates and visible injury ratings. Two plant development stages and four or five leaf growth stages were examined. The LDC varied among leaf growth stages and between plant development stages and leaf surfaces; there was no continuity in the LDC pattern. Sorption rates differed among some leaf growth stages, and between plant development stages in expanding leaves (growth stage 1). For both development stages high sorption rates occurred in fully mature leaves; otherwise little similarity between corresponding leaf growth stages was evident. Total O 3 flux to the leaf was not well predicted by the LDC for water vapour; nor was visible injury well related to total flux. Differential mesophyll processes and leaf surface sorption capabilities may have accounted for some of the inconsistencies observed.

A quantitative estimation of sequential leaf growth of some dryopteroid ferns in Hokkaido with respect to size and shape

Leaf-size and leaf-shape were followed on expanding leaves of mature sporophytes of four Dryopteris species cultivated for more than 7 years in Sapporo. Blade length(BL, cm), leaf length(LL)and blade width(W)were measured. as an indicator of leaf-size, and BL/W and BL/LL ratios were calculated to generate leaf-shape indices during leaf growth from April to June at 2-8 day intervals. Following BL/W changes as a function of LL increase could be used to characterize different stages of leaf growth between Dryopteris laeta and D. austriaca, and between D. crassirhizoma and D. coreanamontana; however both of these two species had almost similar BL/W and LL on-expanded leaves, respectively. The speed of leaf elongation(dLL/dT, cm/day)was also included for characterization of leaf expansion. Based on relative changes(%)between the maximum and minimum values of BL/W, BL/LL and dLL/dT, six categories could be recognized during the process of leaf expansion.

Common Waterplantain,Alisma plantago-aquatica, Control in Wild Rice,Zizania palustris, with MCPA and 2,4-D

Field experiments were conducted to evaluate the effect of application time on common waterplantain control in wild rice with MCPA and 2,4-D. Common waterplantain control was greatest when MCPA or 2,4-D were applied at 1.1 or 1.7 kg ai/ha at the two-aerial leaf stage. The best late-season control was MCPA applied at the scape elongation growth stage. Common waterplantain was controlled adequately when 0.6 to 0.8 kg/ha of MCPA were applied at the scape elongation or early flowering stage. However, because of common water plantain interference and sensitivity of wild rice to late herbicide applications, the best treatment stage for wild rice yield was when MCPA was applied at 0.6 kg/ha to common waterplantain at the two-aerial leaf stage. Wild rice at this time is at the more tolerant one-aerial leaf growth stage.

Sensitivity of Fieldbeans (Phaseolus vulgaris) to Reduced Rates of 2,4-D and Dicamba

The effects of the dimethylamine salt of dicamba (3,6-dichloro-2-methoxybenzoic acid) and the dimethylamine salt of 2,4-D [(2,4-dichlorophenoxy)acetic acid] on fieldbeans (Phaseolus vulgarisL. ‘Great Northern Valley’) were studied in order to assess the potential hazards of using these herbicides in areas adjoining fieldbean production. Dicamba and 2,4-D were applied to fieldbeans at three different rates (1.1, 11.2, and 112.5 g ai/ha) and four different growth stages (preemergence, second trifoliolate leaf, early bloom, and early pod). Application of 2,4-D preemergence or in the second trifoliolate leaf stage of growth did not reduce seed yield, delay maturity, or reduce germination of seed obtained from treated plants. Dicamba or 2,4-D applied at 112.5 g/ha to fieldbeans in the early bloom or early pod stages of growth consistently reduced seed yield, delayed maturity, and reduced germination percentage. Fieldbeans exhibited a greater overall sensitivity to dicamba than to 2,4-D.

Cadmium-Induced Decrease of Water Stress Resistance in Bush Bean Plants ( Phaseolus vulgaris L. cv. Contender) II. Effects of Cd on Endogenous Abscisic Acid Levels

Summary The cadmium content and the endogenous abscisic acid (ABA) levels of roots, stems, primary, and trifoliate leaves of bush bean plants ( Phaseolus vulgaris L. cv. Contender), grown with different Cd concentrations in the medium were analysed. The samples were taken at different plant growth stages: primary leaf growth stage, first trifoliate leaf growth stage, flowering, and fruit development. No correlation between Cd and ABA contents could be established. In roots Cd-toxicity increased ABA levels. In leaves only the lowest Cd concentration increased the ABA content, while in plants treated with higher Cd concentrations no increase in ABA content in response to wilting was observed. Cd at high concentrations is suggested to decrease water stress resistance by inhibition of the hydroactive stomata response.

Response of 17 Species of Container-Grown Woody Landscape and Foliage Plants to Four Postemergence Herbicides

Postemergence applications of 2 rates of Whip [fenoxaprop-ethyl) (ethyl 2-[4-[(6 chloro-2-benzoxazolyl) oxy]-phenoxy] propanoic acid), Assure (quizalofop-ethyl) (2-[4-[6-chloro-2-quinoxalinyl) oxy]-phenoxy]-propanolc acid, Fusilade 2000 (fluazifop-p-butyl) (R-butyl 2-[4-(5) trifluoromethyl-2-pyridyloxy)-phenoxy] propanoic acid), and Poast (sethoxydim) (2-[1-(ethoxyamino) butyl]-5-[2-(ethylthio) propyl 1]-3-hydroxy-2 cyclohexene-l-one) were evaluated for phytotoxicity to 17 species of container-grown woody landscape and foliage plants and control of large crabgrass (Digitaria sanguinalis L.). Crabgrass plants were treated at the 2 to 4 and 8 to 10 leaf stages and were grown under both full sun and 40% shade. Each herbicide injured at least one species. Fusilade 2000 injured the fewest species, while Poast injured the most. Under 40% shade, control of crabgrass with 2-4 leaves was acceptable with all herbicides except 0.28 kg/ha (0.25 lb/A) Whip. All herbicides were effective when applied in the 8-10 leaf stage of growth. In full sunlight, excellent control of crabgrass at the 2-4 leaf stage was obtained with all herbicide treatments except Poast. Two weeks after application to the 8-10 leaf stage, the best control was obtained with Whip; however, by the end of 8 weeks, all treatments, except Poast, provided excellent control.

Tissue-distribution of secondary phenolic biosynthesis in developing primary leaves of Avena sativa L.

Primary leaves of oats (Avena sativa L.) have been used to study the integration of secondary phenolic metabolism into organ differentiation and development. In particular, the tissue-specific distribution of products and enzymes involved in their biosynthesis has been investigated. C-Glucosylflavones along with minor amounts of hydroxycinnamic-acid esters constitute the soluble phenolic compounds in these leaves. In addition, considerable amounts of insoluble products such as lignin and wall-bound ferulic-acid esters are formed. The tissue-specific activities of seven enzymes were determined in different stages of leaf growth. The rate-limiting enzyme of flavonoid biosynthesis in this system, chalcone synthase, together with chalcone isomerase (EC 5.5.1.6) and the terminal enzymes of the vitexin and isovitexin branches of the pathway (a flavonoid O-methyltransferase and an isovitexin arabinosyltransferase) are located in the leaf mesophyll. Since the flavonoids accumulate predominantly (up to 70%) in both epidermal layers, an intercellular transport of products is postulated. In contrast to the flavonoid enzymes, L-phenylalanine ammonia-lyase (EC 4.3.1.5), 4-coumarate: CoA ligase (EC 6.2.1.12), and S-adenosyl-L-methionine: caffeate 3-O-methyltransferase (EC 2.1.1.-), all involved in general phenylpropanoid metabolism, showed highest activities in the basal leaf region as well as in the epidermis and the vascular bundles. We suggest that these latter enzymes participate mainly in the biosynthesis of non-flavonoid phenolic products, such as lignin in the xylem tissue and wall-bound hydroxycinnamic acid-esters in epidermal, phloem, and sclerenchyma tissues.

Nitrogen Accumulation Rates of Irrigated Maize

AbstractImproved fertilizer nitrogen (N) use efficiency in irrigated maize (Zea mays L.) often results from delaying application of moderate N rates until the crop is rapidly growing. The objective of this experiment was to determine how N application time, N rate, and planting date influenced the pattern of N and fertilizer−derived N (FN) accumulation in irrigated maize grown on a deep, productive silty clay loam soil (Typic Argiudoll, fine, montmorillonitic, mesic). A factorial combination of early and late planting, N application at planting, or at the 4−, 8− or 16−leaf growth stage, and two N rates (90 and 180 kg N ha−1 as 15N−depleted ammonium sulfate) were applied to the same plots in 1979–1980. Above−ground plant samples were taken at the 8−leaf, l2−leaf, silking, soft dough, and physiological maturity stages of growth. Average net rates of N and FN accumulation were calculated using a temperature index as the divisor. Rates of N and FN accumulation per plant were greatest between the 12−leaf and silking growth stages in 1979, except when N application was made at the 16−leaf stage where maximum accumulation rates occurred during early grain fill. Effects of N application time on N accumulation rates were more pronounced in 1980 and followed patterns similar to those in 1979. Substantial amounts of residual FN from 1979 accumulated in above−ground tissue in 1980. Residual FN uptake was apparently greater, in comparison to newly applied FN, in the heavily−fertilized or late−planted crop. Time of maximum N accumulation was delayed as time of N application was delayed. Grain yield was reduced by early N deprivation only when active N uptake ceased during early grain fill. Excessive N application minimized the effect of application time on final grain FN content. Delayed planting reduced FN recovery at both levels of N fertilization. Relative recovery of FN in maize grain was maximized by applying the low N rate late in vegetative growth, irrespective of planting date.

Changes in RuDP Carboxylase Activity of Rice Leaf Blade at Various Growing Stages

Ribulose-1, 5-diphosphate (RuDP) carboxylase, catalase and acid phosphatase activitics, and chlorophyll and soluble protein contents expressed in term of unit leaf area were investigated at various stages of leaf growth in pots. The following results were obtained : (1) When the leaf blade was divided into three equal parts, RuDP carboxylase activity of each part of young leaf blade immediately after it had fully expanded showed the ranking order: middle≥top<base. The activity of the aged old leaf showed the ranking order: base<middle<top. But the mean activity in the whole leaf blade was considerably lower in older leaf than in expanded younger one. Changes in RuDP carboxylase activity also had a similar pattern to soluble protein content, but not to chlorophyll content in all leaf parts. (2) When RuDP carboxylase activity in different position of leaf blades was measured at various stages of leaf growth, the results were obtained that the mature top leaf which completely expanded had the highest activity and as the leaf positions dropped down, RuDP carboxylase activity of each leaf decreased drastically. RuDP carboxylase activity of developing immature leaf was as low as that of lower leaf position. Chlorophyll content of leaf blade attained its maximum at the lower leaf than the mature top leaf and their differences among various leaf positions were observed after young panicle formation stages, but not at early growing stages. (3) After heading date, RuDP carboxylase activity of flag leaf was maintained at relatively higher levels untill toward the yellowing stages. During these stages, soluble protein content, chlorophyll content, and catalase activity of each leaf changed parallel with RuDP carboxylase activity, respectively, but acid phosphatase activity increased with the ageing of expanded leaf blades. (4) The correlation evident between RuDP carboxylase activity and soluble protein content observed through the growing stages (table 3 and 4.) indicated that there was a parallel correlation between RuDP carboxylase activity and photosynthetic rate when we referd to the past some observations that protein-nitrogen content of rice leaf was closely correlated with the photosynthetic rate. Chlorophyll content also changed parallel with the RuDP carboxylase activity through growing stages except for the early stages. But the degree of the parallelism between the two was lower than that between RuDP carboxylase and soluble protein content.

Selective chemical control of doublegee (Emex australis) in legume pasture

Seven chemicals were evaluated for selective control of doublegee (Emex australis) in legume pasture in 14 field trials conducted at several sites in Western Australia over three years. The effect of removing doublegee on pasture growth was studied in four field trials over the same period. Three hundred and fifty to 700 g a.i. methabenzthiazuron ha-1 gave good selective control of this weed except at Chapman and Wongan Hills in 1974 where the beginning of the growing season was poorly defined. The selectivity of bromoxynil and WL 6361 1 in one year of trials was similar to methabenzthiazuron but that of asulam and metoxuron was too restricted for practical use when doublegees were sprayed at the 2-4 leaf growth stage, 2,4-DB showed selectivity on doublegees with 12 leaves, and no herbicides were satisfactory on doublegees with more than 12 leaves at the time of spraying. Pasture growth and clover seed production was not substantially increased by controlling doublegee.

Water Potential and Stomatal Resistance of Sunflower and Soybean Subjected to Water Stress during Various Growth Stages

Plants of two varieties of soybean (Glycine max (L.) Merr.) and two varieties of sunflower (Helianthus annuus L.) were grown in controlled environments and subjected to water stress at various stages of growth. Leaf resistances and leaf water potentials were measured as stress developed. In soybeans the upper leaf surface had a higher resistance than the lower surface at all leaf water potentials and growth stages. Resistance of the upper surface began to increase at a higher water potential and increased more than the resistance of the lower surface. Resistances returned to prestress values 4 days after rewatering. In sunflowers upper and lower leaf surfaces had similar resistances at all water potentials and growth stages. Leaf resistances were higher in sunflower plants stressed before flowering than in those stressed later. Sunflower plants stressed to -16 bars recovered their prestress leaf resistance and water potential a few days after rewatering, but leaves of sunflower plants stressed to -23 bars died. Leaves of soybean and sunflower plants stressed before flowering suffered less injury than those of older plants and sunflowers stressed after flowering suffered more injury than soybeans.

Response of Snap Bean to Seed Separation by Aerodynamic Properties1

Abstract Seed of 11 cultivars of snap bean, Phaseolus vulgaris L., were separated by aerodynamic properties in a vertical air column. Seed physical characteristics associated with air column separation were weight, density, volume, diameter, and length. The separation technique did not affect seed germination, seedling emergence, or plant survival at full expansion of the first trifoliate leaf growth stage. However, seed remaining in the air column after aspiration produced fewer weak plants and fewer plants with root rot at the first trifoliate leaf. These seed produced a greater plant stand, a greater pod weight per plant, a more uniform pod size distribution, and a greater yield at harvest than the seed removed. Yield from seed remaining after air column aspiration was 21% greater than from non-graded seed.

CONTRIBUTION OF STEMS AND LEAVES TO THE YIELD AND NUTRIENT LEVEL OF IRRIGATED ALFALFA AT DIFFERENT STAGES OF DEVELOPMENT

In Roamer alfalfa (Medicago media Pers.) the nutritive value in leaves deteriorated much more slowly than that in stems. The percentage of N declined 29% in leaves and 49% in stems; percentage P declined 4% in leaves and 34% in stems, and percentage digestible energy declined 3% in leaves and 34% in stems between early leaf and late bloom growth stages. The total yield of nutrient increased rapidly to the early bloom stage, but quite slowly thereafter. Because of possible leaf loss, delayed harvesting of an alfalfa crop beyond the mid-bloom stage would not be warranted to gain yield even when only one cutting is taken.

Gene Pm5 for Resistance to Erysiphe graminis f. sp. tritici in Hope Wheat1

‘Hope’ wheat (Triticum aestivum L.) is known to be resistant to certain cultures of the powdery mildew fungus, Erysiphe graminis DC. f. sp. tritici Em. Marchal. We inoculated parental, F2, and F3 populations from crosses of Hope with four lines near‐isogenic for Pm1, Pm2, Pm3a, and Pm4, with three cultures of the powdery mildew fungus. Our data showed that Hope has a single, recessive gene pan: that conditions resistance to the fungus and that the gene is different from Pm1, Pm2, Pm3a, and Pm4. The symbol Pm5 has been assigned to the Hope locus. The phenotype of pm5 is best expressed when the host is inoculated at the four to five leaf stage of growth. Reaction of Hope is characterized by marked chlorosis surrounding lesions.

PLASTID DEVELOPMENT IN PRIMARY LEAVES OF PHASEOLUS VULGARIS

SummaryBy the use of light and electron microscopy a quantitative investigation has been made of plastid membrane formation in the primary leaves of bean plants, during germination and growth in the dark. From 4 to 14 days of dark growth there was an eleven‐fold increase in cell number and a twenty‐six‐fold increase in plastid number per leaf. Formation of plastid envelope membrane between 6 and 14 days of dark growth amounted to 98 cm2 of membrane per leaf while the corresponding formation of internal plastid membrane was 272 cm2 per leaf. This internal plastid membrane appears to be formed, at least during the early stages of leaf growth, by the invagination of the inner envelope membrane. When a substantial amount of the thylakoid membrane has accumulated in the plastid a condensation process takes place to give the pro‐lamellar body, which is a structure composed of branching membrane tubules. Calculations based on the dimensions of these tubules have established that 1 μ3 of prolamellar body contains about 44 μ2 of membrane.Dark‐grown leaves have been found to contain all of the enzymes of the photosynthetic carbon cycle. The course of development, during dark growth, has been determined for the activities of eight enzymes of the photosynthetic carbon cycle and for two enzymes of the cytoplasm.

Effects of Herbicides Applied Postemergence on Weeds and Sunflowers1

Herbicides were applied as postemergence treatments either as early over‐the‐top spray or late‐directed spray to sunflowers (Helianthus annuus L.) for weed control and crop tolerance determinations at Experiment, Ga. Treatments of RP 17623 (2‐tertiobutyl‐4‐(2,4‐dichloro‐5‐ isopropyloxyphenyl)‐5‐oxo‐l,3,4‐oxadiazoline) were applied to sunflowers in the cotyledon, first leaf, and second leaf growth stages. Several herbicides commonly used on other crops were applied late postemergence directed spray to sunflowers when they were 25 to 35 cm tall.were obtained from early postemergence treatments of RP 17623 when applied as over‐the‐top spray at either the cotyledon or the first‐leaf stage of sunflower growth. Weed control results were similar to RP 17623 from several herbicides that were applied as late‐directed postemergence sprays. Early postmergence treatments with RP 17623 caused some early injury to sunflower plants and a reduction in achene oil percent when compared with achenes from untreated plants, but achene yields were not reduced. None of the herbicides applied as late‐directed postemergence sprays injured sunflowers, reduced achene yield, or achene oil percent.

Photosystem II Activity in Agranal Bundle Sheath Chloroplasts from Zea mays

The photochemical activities of chloroplasts isolated from bundle sheath and mesophyll cells of maize (Zea mays var. DS606A) have been measured. Bundle sheath chloroplasts are almost devoid of grana, except in very young leaves, while mesophyll chloroplasts contain grana at all stages of leaf development.Chloroplast fragments isolated from bundle sheath cells showed a light-dependent reduction of potassium ferricyanide, 2, 6-dichlorophenolindophenol, mammalian cytochrome c, plastocyanin, and Euglena cytochrome c(552). These activities were inhibited by 3-(3, 4-dichlorophenyl)-1, 1-dimethylurea at 1.25 micromolar. However, the photoreduction of NADP from water was extremely low or absent, except in chloroplasts from very young leaves, and the capacity for NADP reduction appeared to be related to the degree of grana formation.Photosystem I activity was present in bundle sheath chloroplast preparations at all stages of leaf growth and senescence examined. However, the activity was lower than in isolated mesophyll chloroplasts. NADPH diaphorase activity was comparable in both types of chloroplast.Chloroplasts isolated from bundle sheath cells of plants grown under a variety of conditions, including continuous and intermittent light, high and low light intensities, and high temperature, exhibited photosystem II activity.

The effect of seed size on seedling growth in subterranean clover (Trifolium subterraneum L.)

The effect of seed size on seedling growth in a single population of Daliak subterranean clover was studied by growing individually weighed seeds to the third trifoliate leaf stage in three controlled environments. The environments were: 18°C at high light intensity (27,000 lux), 12° at high light intensity, and 18° at low light intensity (5400 lux). Plant weight at emergence exceeded the weight of embryo in the original seed, owing in part to the utilization of endosperm. At emergence the ratio of plant weight to seed weight increased with increasing seed size. Nevertheless, in all environments the smaller seeds ultimately produced relatively larger plants owing to a higher relative growth rate, particularly during the cotyledon and unifoliate leaf stage of growth. Higher relative growth rates in seedlings from smaller seeds were associated with higher leaf area ratios resulting from the production of relatively larger cotyledon and individual leaf areas in all environments. More rapid leaf expansion in seedlings from larger seeds progressively offset this advantage.

DETECTION AND EVALUATION OF PLANT GROWTH RESPONSES TO ENVIRONMENTAL CONDITIONS

The rate of leaf development was used for detecting and evaluating growth responses of carnations to environmental factors. Studies were conducted in two separate greenhouses with different temperature, humidity, and soil moisture conditions. Quantitative morphological stages of leaf growth were recorded on a daily basis until buds formed at which time daily bud diam measurements were begun. The cumulative data were transformed into growth rates. Environmental data were obtained daily. Lags in the effect of each environmental factor on growth were obtained by simple correlation analyses using environmental data on the day of growth and each of five previous days. Multiple regression analyses using leaf growth rate or bud growth rate as the dependent variable and environmental data with appropriate lags as independent variables were conducted to determine the relationship of the various environmental factors to growth rate. Equations were developed to predict plant growth under varying environmental conditions.

Physiological and ecological studies on the oestrogenic isoflavones in subterranean clover, (T. subterraneum L.) VIII. Phosphate supply in relation to temperature and to leaf development

In recently expanded first trifoliate leaves of the Dwalganup strain of subterranean clover, the relative difference for concentrations of formononetin at low and high phosphate supply levels was about the same at 12.5, 22.5, and 32.5�C. However, absolute differences were much less at the high temperature, where concentrations were also low. The concentrations of the other isoflavones, genistein and biochanin A, were much less affected by phosphate supply than was formononetin. Effects of phosphate on isoflavone concentrations were already evident at leaf emergence; and in phosphate-deficient leaves, concentrations of isoflavones - especially formononetin - increased during the later stages of leaf growth. Isoflavone production per leaf cell seems to be dependent on the supply of carbon substrates in the form of sugars and starch.