Influence Of Leaf Research Articles

Ocena użyteczności metody Bikermana do wyznaczania kątów zwilżania liści

The physico-chemical properties of the spray liquid affect the efficiency and effectiveness of crop protection treatments. A measure of leaf wettability is the wetting angle, the testing of which is neglected in routinely performed spraying. In the search for a method useful for determining leaf wetting angle for crop protection treatments, the method that Bikerman (1941) applied to the surface of the object observed from above was evaluated. The assumptions of the method and the resulting opportunities and constraints in its application are presented in this paper. The influence of leaf, liquid and droplet properties on the wetting angle was discussed. It was concluded that Bikerman’s method is suitable for determining leaf wetting angles over a wide range of physical properties of liquids used in crop protection treatments.

Influence of Leaf/ Bunch Ratio on Yield and Fruit Quality of “Zaghloul” Dates

Different pruning ‎patterns of leaves in relation to a number of bunches (leaf/bunch ratio) ‎‎during the 2018 ‎and 2019 seasons were applied to uniform‏ ‏‎12 adults‎‏ ‏of 17-year-old ‘Zaghloul’ date ‎palm ‎females grown on sandy soil under drip irrigation in Belbis district, Sharkia ‎Governorate, ‎‎Egypt. Three levels of leaf/bunch ratios at 6:1, 8:1, and 10:1 plus the control ‎treatment ‎ ‎(only dead leaves were cut) were investigated. The tested physical characteristics were ‎yield, ‎ weight of bunch, fruit and fruit flesh, as well as fruit length and diameter, and dry ‎weight ‎of flesh of date fruits. In addition, the total soluble solids content and Tannins ‎as ‎chemical characteristics of date fruits were measured. All pruning treatments increased the yield/palm in ‎comparison ‎‎with the control. The leaf/bunch ‎ratio at 10:1 achieved the highest yield (182.06 ‎and184.50 ‎kg/palm) in the two seasons, respectively. The palm yield of check treatment was ‎lower with results of 135.22 and 136.00 ‎kg/palm in the studied seasons, respectively. Palms in all levels of leaf/bunch ratios recorded the highest of the bunch weight and fruit weight of dates in comparison with those in palms had no pruning. ‎Generally, all applied leaf/bunch ratios had a positive ‎effect on other measured physical ‎properties of ‘Zaghloul’ date palm fruits. The total soluble solids content was higher in ‎pruned palms, however, the tannins percentage was lower in the same palms. The ‎leaf/bunch ‎‎10:1 ratio gave the best results regarding the tested characteristics of ‎‎‘Zaghloul’ date ‎palms under the ‎studied region.‎

Allelopathic influence of leaf and leaf litter of white cedar (Melia azedarach L.) on eggplant and okra

Allelopathic influence of leaf and leaf litter of white cedar (Melia azedarach L.) on eggplant and okra

Influence of leaf and canopy characteristics on rainfall interception and urban hydrology

ABSTRACT Considering the rapid expansion of urban populations and the corresponding urbanization of landscapes, a dearth of knowledge exists regarding the role of urban vegetation in modulating urban ecosystem functioning. In response to the need for the development of new approaches to quantify ecohydrological processes along urban-to-rural gradients at alternate scales, this study explores the relationship between individual plant selection choices in landscaping and changes in urban hydrological functioning. This research examines differences in the variation of rainfall interception, leaf hydrophobicity, canopy structure, and water storage, between 13 species in an urban, semi-arid location. The species studied were selected based on resident preferences, and hence this research considers the role that urban residents play, through individual choices, in modifying the ecohydrology of an urban watershed. Rainfall interception, canopy surface storage, leaf hydrophobicity, and water droplet retention were significantly different between species. Results indicate that individual choice in plant selection for landscaping may influence urban hydrology.

Influence of leaf and silique photosynthesis on seeds yield and seeds oil quality of oilseed rape (Brassica napus L.)

With the purpose of enhancing oil production, the present work was carried out to elucidate relationships between photosynthesis of leaves, siliques and seeds yield and seeds oil accumulation of oilseed rape. Field trials, in which two repeated experiments was carried out during 2012–2014 growth season, a rape hybrids the “Qin You No.7” (Brassica napus L.) variety was taken into account. The results showed that, on rape plant the photosynthetic capacity and chlorophyll a, b, carotenoid contents of leaf were significantly higher than that of silique shell. Oil content of 94.7% was achieved in young seeds (sampled at 25th day after flowering ending stage of the tested rape plant) versus to mature seeds, saturated fatty acids percent was higher whereas oleic acid percent was lower of oil extracted from young seeds. During flowering period of the rape plants tested, area and dry weight of leaves attained maximum, treatments of removing leaves induced reduction in seeds number per silique, siliques number, seeds yield per plant and seeds oil content, these indexes were respectively decreased by 73.6%, 43.4%, 83.4% and 10.5% in maximum, and seeds oil composition was not significantly influenced; during seeds growing period of the tested plants, surface area and dry weight of siliques attained maximum, under shading siliques treatment, the 1000-seed weight, seeds yield per plant and seeds oil content were respectively reduced by 57.5%, 61.4% and 44.7% in maximum, and seeds oil oleic acid (C18:1) and linolenic acid (C18:3) percent was decreased, linolic acid (C18:2) and erucidic acid (C22:1) percent was increased. So for oilseed rape plant during flowering period, surface area and photosynthesis of leaves dramatically influenced siliques number, seeds number and seeds yield; while in seeds growth period, surface area and photosynthesis of siliques greatly influenced 1000-seed yield, seeds yield, seeds oil content and oil composition; oil accumulation in rape seeds initiated early since seeds commencing growth, seed mature degree influenced oil composition of seeds.

Demand-driven fertilization. Part I: Nitrogen productivity in four high-maintenance turf grass species

The effect of four nitrogen (N) availabilities on growth, leaf N concentration, N productivity (dry matter production per unit time and unit N taken up), shoot:root ratio and carbohydrate storage was studied in velvet bentgrass (Agrostis canina ‘Legendary’), creeping bentgrass (A. stolonifera ‘Independence’), slender creeping red fescue (Festuca rubra ssp. trichophylla ‘Cezanne’) and chewings fescue (F. rubra ssp. commutata ‘Center’). In growth chamber experiments, plants were grown for 3 weeks in sand with 12.5, 25, 50 or 200 mg N L−1 in the irrigation water and at two mowing intensities, cut at 5 mm twice per week or uncut. It proved possible to control important turf grass traits such as shoot growth rate, shoot:root ratio, leaf morphology and carbohydrate storage through leaf N concentration. The relationship between leaf N concentration and aboveground growth was linear for both cut and uncut turf. The relative N demand of the studied species, based on their N productivity, was 1:0.67:0.67:0.37 for creeping bentgrass, velvet bentgrass, chewings fescue and slender creeping red fescue, respectively. Clipping significantly reduced N productivity, and hence turf N demand. The lowest possible leaf N concentration without adverse effects on plant health and appearance was between 3.1 and 3.5% of dry matter (DM) in both bentgrasses and fescues. This value can be used as a target in minimizing fertilizer usage and N leaching losses. In conclusion, fertilization based on the influence of leaf N concentration on growth-related processes offers possibilities to control growth in a predictable and desirable manner under varying climate and growth conditions. This could provide more environmentally friendly and economic fertilization regimes and also better playing quality.

Variability and correlations between characteristics in pumpkin varieties (Cucurbita maxima Duch. ex Lam.)

Variability and correlations among morphological features of eight ornamental pumpkin varieties were studied under field conditions. The variability of plant height, fruit length, fruit width, fruith weight, fruit peel thickness, length and circumference of handle grip, leaf length, leaf width, seed length, seed width, seed thickness and number of fruits per plant in the examined material was high. The highest variability was related to the fruit properties. This variability represents a good source for future breeding programs. Correlations between the traits indicated a significant influence of leaf and seed characteristics on fruit properties. Multivariate statistical analysis provided differentiation of varieties on two phenotypically different groups.

Poster - Thurs Eve-24: Dosimetry study on the penumbra region for the irregular MLC fields with stepping patterns.

The aim of this study is to investigate the dosimetric effect in the penumbra region for the multi-leaf collimator (MLC) fields with stepping patterns. Various irregular MLC fields with different stepping patterns were designed. Radiographic films were used to measure the beam profiles (cross-plane (X1-X2 jaw) and in-plane (Y1-Y2 jaw)) for different MLC field configurations of varying lengths of protruded leaves adjacent (on one or both sides) to the beam profile axis. 6 MV photon beams produced by the Varian 21 EX linear accelerator with 120-leaf Millennium MLC were used. The results showed that the penumbra widths (10% - 90%) of the profiles (cross-plane) with 0.5 cm gap width increased with the protruded lengths of the neighbouring leaves, while the penumbra widths did not vary too much for the larger gap widths of 1 cm and 1.5 cm. The neighbouring leaf's influence on the profile was very insignificant, when the distance between the profile and neighbouring leaf edge was larger than 1 cm. Moreover, when both the upper and lower portions of leaves were moved out forming a gap for the profile, the dose at the "edge" region was decreased by about 20% and 6% when the protruded lengths of the leaves were 0.5 cm and 1 cm, respectively. It is important to understand the dosimetric effect in the penumbra region for irregular MLC fields with stepping leaf patterns, especially during the commissioning process for the conformal external beam and intensity modulated radiation therapy.

Influence of leaf, humidity and applied lubrication on friction in the wheel-rail contact: Pin-on-disc experiments

A novel test method has been used to study how applied and natural lubrication (leaf and humidity) influences the coefficient of friction in the wheel-rail contact. A pin-on-disc tribometer placed in a climate chamber was used as the test equipment. The pin-on-disc contact simulates the wheel-rail contact caused by commuter train traffic on straight track. The results show that the coefficient of friction decreases when the relative humidity increases and decreases even more when a leaf is used as a lubricant. By using an elm leaf as the lubricant, the coefficient of friction is reduced by a factor of four compared with the unlubricated case. However, the coefficient of friction decreases even more when a rail lubricant is used.

Effects of Developing Leaves on Stelar Pattern Development in the Shoot Apex of Matteuccia struthiopteris

A developmental study of the normal shoot apex of Matteuccia struthiopteris suggested that patterned stelar differentiation is initiated immediately beneath the single layer of promeristem and occurs prior to the initiation of the youngest leaf primordium. A developmental study in which all leaf primordia were suppressed, with or without lateral isolation of the terminal meristem by vertical incisions, has confirmed this interpretation of stelar differentiation. Experimentally-induced changes in the tissue immediately below the promeristem were reflected in the resulting mature structure of the stele. Failure of leaf gap initials to differentiate, if all leaf primordia were suppressed at the incipient stage, resulted in a mature stele without leaf gaps. Similarly the disappearance of pith mother cells after several weeks of leaf removal was associated with the formation of a stele without pith. Leaf influence was further assessed by allowing one primordium to develop while all others were suppressed. The developing leaf had a small promoting effect on cauline vascular tissue differentiation but its major impact on the expansion of the parenchymatous tissues of the stele. Characteristic protoxylem and protophloem failed to differentiate when all leaves were suppressed and, when leaf was allowed to develop, formed only in relation to the leaf.

The influence of leaf and stem particle size in vitro and of sample size in sacco on neutral detergent fibre fermentation kinetics

Four particle sizes, chopped, ground to pass a sieve of 4.5 mm (coarse ground), 1 mm (medium ground) and 0.25 mm (fine ground) of early and late cut winter wheat were separated into leaf and stem fractions and incubated with rumen fluid in vitro for 0–148 h in a first experiment. In a second experiment, grass hay (GH) and wheat straw (WS), ground to pass a 2 mm sieve were incubated in sacco for 0–185 h. Sample size varied from 3.75 to 22.5 mg cm −2 bag surface area for GH and from 7.5 to 22.5 mg cm −2 bag surface area for WS. An exponential model with and without lag was fitted to the curves in both experiments using relative values of residual neutral detergent fibre (NDF). Treatments were tested for effects on curve displacement (any curve parameter differences) and on rate and lag of fermentation. Results from the first experiment showed a higher average rate of degradation for leaves over stems and a negative effect of cutting date. Undegradable NDF was lower for early cut stems and higher for late cut stems. Particle size had a significant effect on curve displacement in all cases. Specific effects on lag were significant in all cases except for early cut stems and on rate only for early cut leaves. The greatest effect on lag ( P < 0.001) and rate (NS) was seen in late cut stems. In sacco WS rate was approximately half that of GH and undegradable NDF was 0.38 as compared with 0.21 for GH. Sample size in sacco had a significant effect on both rate and curve displacement for GH but not for WS. There seemed to be no effect on undegradable NDF in either experiment.

Influence of leaf and branch slope on Stemflow amount

Experiments were carried out in the laboratory under a rainfall simulator to evaluate the effect of the varying slope angles of catching surfaces on stemflow amounts. Stemflow was measured on three different types of surfaces: Molinia grasses, single branches, maquette of a maize leaf. For each of them three intensities were used. Taking into account the vertical projection of the surface (cosα) and the gravitation (sinα) we expected theoretically maximum stemflow amounts at slope angles α around 40°–50°. Experimental results of stemflow on grasses do not differ greatly from those values: maxima were obtained at 50°–70°. However measured maximum stemflow amounts on maize leaves and branches were reached already around 5°–20°.

Photosynthetic Rates of Six Maize Cultivars During Development

AbstractProduction estimates based on photosynthate accumulation are affected by changes in photosynthesis rates related to aging in different cultivars. The influence of leaf and plant age on photosynthetic rates was investigated in six maize (Zea mays L.) cultivars with maturity ratings ranging from &lt;2300 to &gt;3500 CHU (corn heat units). Photosynthesis and irradiance measurements were fitted to rectangular hyperbolas using a nonlinear fitting technique. These curves were analyzed as a function of cultivars, and leaf and plant age. For comparison among cultivars and age groups, photosynthesis was represented by P2000 (net photosynthetic rate at irradiance (I) = 2000 µmol m−2 s−1). In all cultivars, early leaves had lower P2000 values at a given leaf age than late maturing leaves. The P2000 values tended to increase to a maximum at the time of full individual leaf expansion and then decrease. The duration of maximum P2000 values for leaves nearest the ear were longer than for earlier or later developing leaves. Leaves nearest the ear for early maturing cultivars tended to have lower P2000 values than later maturing cultivars at comparable leaf ages. Plant photosynthesis patterns were the same for all cultivars in relation to plant age and phenological development. Photosynthesis (P2000) was low for the six‐leaf stage, reached a maximum just before tasselling, and then declined during brown silk, blister, and dent stages. A quadratic equation described the relationship between P2000 and plant age. The trend was for latermaturing cultivars to have significantly (P &lt; 0.05) larger P2000 values than earlier‐maturing cultivars at comparable phenological stages. Significant cultivar differences were found in leaf development rate and length of vegetative period (P &lt; 0.10).

Nonsteady-state analysis of water flow and capacitance for Agave deserti

An analog electrical circuit, including both resistances and capacitances for roots, stem, and leaves, was developed for a desert leaf-succulent, Agave deserti. Based on soil water potentials and observed transpiration rates and the influence of leaf, stem, and root relative water content on the water potential of each organ, water potential could be predicted at various locations in the transpiration stream. Simulations indicated that as stomata opened at night for this crassulacean acid-metabolism plant, most of the water initially transpired came from the leaves. Water movement from the soil was greatest throughout the night and the early morning; the maximal water uptake rate from the soil was only about half of the maximum transpiration rate. As drought increased, lower transpiration rates led to smaller water losses, in turn leading to progressively earlier recharge of the leaf capacitance. The substantial and predictable daily changes in plant water potential may have profound effects on physiological processes in the cells near the transpiration stream.

Tiller Bud Inhibition by Young Foliage Leaves in Jointing Wheat1

Young foliage leaves have been associated with bud inhibition in dicotyledonous plants. Whether or not young leaves influence tiller buds in a grass is important, and particularly so in species repeatedly mown or grazed for herbage since the regrowth arises primarily from new tillers. ‘Sonora 64’ wheat (Triticum aestivum L.) during the jointing stage possessed the tiHering characteristics desired for this investigation.The influence of removing selected leaf laminae on stems retaining the shoot apex was studied on plants in the greenhouse and on uprooted culms in growth chambers. Basal axillary buds on these culms were exposed by stripping off the sheaths of lower leaves. The greatest bud elongation was obtained on culms devoid of foliage leaf blades. Less bud elongation occurred in the presence of an intact flag leaf, and still less if several of the younger leaves retained laminae. On plants in the greenhouse, removal of the younger leaves delayed tiller senescence,i ncreasedt he numbeorf tillers surviving the heading stage, and resulted in the resumption of tillering after heading. These responses were indicative of conditions favoring tiller growth. Tiller bud elongation in Sonora 64 was suppressed on culms retaining the younger foliage leaves. Such leaf influence should be considered among the factors regulating tillering.

Inflorescence Formation in Olive as Influenced by Low Temperature, Photoperiod, and Leaf Area

A study was made to ascertain both the organ or organs of perception of low temperatures and the degree of localization of the flowering response to low temperatures, and to determine the relation of photoperiod and leaf area to the low-temperature requirement for flowering in the olive (Olea europaea L.). It was found that the flowering response to low temperatures is localized in the portion of the tree exposed to such temperatures. Localized chilling treatments show that it is not necessary to chill the leaf blades in order to stimulate inflorescence formation, provided the stem and buds are chilled. With respect to inflorescence formation, experiments indicate that the olive is a day-neutral plant, with an obligate low-temperature requirement. Leaf area is important for inflorescence formation, but as little as 10% of the leaf area on small girdled shoots is sufficient to promote normal numbers of inflorescences. The influence of leaves on inflorescence formation is not translocated from one scaffold branch of a tree to another. Inflorescence formation on a small shoot, however, is influenced by the leaves on the surrounding parts of the tree, and this influence is intercepted by removing a ring of bark which includes the phloem. Darkened leaves, under certain conditions, promote inflorescence formation. Even though the leaves do not seem to be involved in the perception of low temperatures, it appears that low temperatures and the leaf influence must act concurrently in order to stimulate inflorescence formation.