Influence Of Leaf Removal Research Articles

Influence of leaf removal on grape, wine and aroma compounds of Vitis vinifera L. cv. Merlot under Mediterranean climate

Influence of leaf removal on grape, wine and aroma compounds of Vitis vinifera L. cv. Merlot under Mediterranean climate

The influence of leaf removal on tuber yield and fuel characteristics of Helianthus tuberosus L. in a semi-arid area

Jerusalem artichoke (Helianthus tuberosus L.) is an important source of biomass for bioethanol production. To evaluate the potential, feedstock and tuber yield, calorific value, and ash content were investigated using different leaf removal treatments in 2013 and 2014 in Inner Mongolia, China. Tuber yield was significantly higher in plants from which the lower 1/3 and 1/4 of the leaves were removed than that in control plants. Tuber yield decreased significantly when an even number or the flank 1/2 of the leaves were removed. Highest tuber yields were obtained under the lower 1/3 leaf removal treatment: 163.98 g/plant in 2013 — 97.40% greater than that of the control treatment, and 149.68 g/plant in 2014. Calorific value and ash content of each plant organ did not vary among leaf removal treatments. Further, calorific values of the stems and tubers were higher than those of other organs, including roots, leaves, and flowers (P <0.05). Leaves showed the lowest calorific values but the highest ash content. Stem and tuber ash was lower than in other organs, while calorific value and ash content were inversely correlated. Our results suggest that removing the lower 1/4 to 1/3 of the leaves is a feasible method for improving Jerusalem artichoke tuber yield and quality.

Influence of leaf removal and reflective mulch on phenolic composition and antioxidant activity of Merlot, Teran and Plavac mali wines (Vitis vinifera L.)

Two years study was conducted to evaluate if leaf removal and red geotextile reflective mulch affect phenolic composition of wines from three red wine grape cultivars, Merlot, Teran and Plavac mali (Vitis vinifera L.). Leaf removal (LR) and reflective mulch (RM), made from weave of aluminum platelets protected by a transparent film and sewn together with red polypropylene threads, were tested separately and combined (LR+RM) on vines of Merlot, Teran and Plavac mali in 2009 and 2010 years, and compared with untreated control. All treatments were applied at veraison. LR had the strongest influence on phenolic composition of experimental wines, particularly in terms of increasing gallic acid, catechin, malvidin-3-glucoside, delphinidin-3-glucoside and peonidin-3-glucoside content. LR+RM resulted in higher gallic acid and malvidin-3-glucoside concentrations. RM treatment had the least effect on phenolic composition of wines but still affected higher epicatechin and gallic acid content. The total phenols, anthocyanins and flavan-3-ols contents in wines exhibited strong correlation with antioxidant activity.

Influence of leaf removal and reflective mulch on phenolic composition of white wines

&lt;p style="text-align: justify;"&gt;&lt;strong&gt;Aim&lt;/strong&gt;: The aim of this research was to evaluate if leaf removal and red geotextile reflective mulch “Vitexsol” could affect phenolic composition of wines from three white cultivars, Riesling italico, Traminer, and Manzoni bianco.&lt;strong&gt;&lt;/strong&gt;&lt;/p&gt;&lt;p style="text-align: justify;"&gt;&lt;strong&gt;Methods and results&lt;/strong&gt;: A two-year study was conducted to evaluate the effects of leaf removal and reflective mulch on the phenolic composition of white wines from Zagreb vineyards in northwestern Croatia. Leaf removal (LR) and reflective mulch (RM) “Vitexsol”, made from weave of aluminum platelets protected by a transparent film and sewn together with red polypropylene threads, were tested separately and combined (LR+RM) on vines of Traminer, Riesling italico and Manzoni bianco in 2008 and 2009. LR and RM had no consistent effect on must sugar content and titratable acidity. All treatments resulted in higher total phenol and flavan-3-ol content in wines of all cultivars, but in different years. LR+RM generally resulted in the highest phenolic acid and individual flavan-3-ol content in all wines except Traminer. RM treatment had the least effect on phenolic composition of wines.&lt;/p&gt;&lt;p style="text-align: justify;"&gt;&lt;strong&gt;Conclusion&lt;/strong&gt;: LR+RM generally resulted in the highest content of most phenolic compounds, especially when compared to control wines.&lt;/p&gt;&lt;strong&gt;Significance and impact of the study&lt;/strong&gt;: This work provides some useful informations for adjusting vineyard practices and thus optimizing phenolic quality of white wines.

Responses of group and individual leaf photosynthetic characteristics of two summer maize (Zea mays L.) to leaf removal under high plant density

Liu, T.-N., Gu, L.-M., Xu, C.-L. and Dong, S.-T. 2014. Responses of group and individual leaf photosynthetic characteristics of two summer maize (Zea mays L.) to leaf removal under high plant density. Can. J. Plant Sci. 94: 1449-1459. The present experiment was conducted during the growing seasons of 2012 and 2013 using two summer maize (Zea mays L.) cultivars, Zhengdan958 (a compact cultivar) and Jinhai5 (a semi-compact cultivar) grown at a plant density of 105 000 plants ha-1, to evaluate the influence of leaf removal on canopy apparent photosynthesis (CAP), individual leaf photosynthetic characteristics and grain yield. Plants were subjected to the removal of two (S1), four (S2) or six leaves (S3) from the top of the plant 3 d after anthesis (DAA), with no leaf removal as control (S0). The results of 2 yr indicated that with increased intensity of leaf removal, the transmission of light to lower strata of the canopy increased. With the removal of two leaves (S1), CAP increased and longer durations of C...

Influence of Leaf Removal, Rootstock, and Training System on Yield and Fruit Composition of Pinot noir Grapevines

A factorial designed experiment was used to vary leaf removal, rootstock, and training system of Pinot noir grapevines during two seasons. Defoliation consisted of 0, 2, 4, 6, 8, or 10 main leaves removed acropetally from the shoot base six weeks after full bloom (pea-size). 3309C and 101-14 Mgt were used as rootstocks, and the training systems used were the traditional low-head, cane pruned system (double Guyot), with an undivided canopy, or a variant with a divided trunk structure having a greater amount of two-year-old and older wood. Total yield and yield of sound fruit was reduced as leaf area decreased. Total yield was higher on vines grafted to 101-14 Mgt, but so was the amount of diseased fruit. Fruit yield showed a clear positive relationship with trunk volume. Yield reduction due to defoliation or rootstock was mainly the result of reduced berry weight. Fruit composition was influenced by defoliation and trunk volume; °Brix and pH declined with increasing level of leaf removal and increased with increasing trunk volume. These data suggest that evaluation of training system choice should include the amount of two-year-old and older wood, since even small amounts (&lt;10% of total) resulted in significant impact on vine growth, yield components, and fruit composition.

LEAF REMOVAL INFLUENCES CANOPY STRUCTURE, BUNCH ROT AND YIELD WITH VITIS VINIFERA L. CVS. OPTIMA AND CABERNET FRANC.

Leaf removal treatments were applied to Vitis vinifera L. cvs. Optima and Cabernet Franc in the Canadian Niagara Region in 1992. Treatments consisted of removing 0% (no leaves), 50% (every other leaf) and 100% (all leaves) from the shoot origin to the most distal cluster when berries were pea-sized. Data was collected on canopy structure, occurrence of bunch rot (Botrytis cinerea Pers.:Fr.), yield, must and wine quality. Application of the 50% and 100% leaf removal (LR) treatments reduced leaf layer number (LLN), percent interior leaves (PIL) and percent interior clusters (PIC) with both cultivars. The influence of LR on LLN, PIL and PIC was greatest for the 100% treatment compared to 50% and 0% This resulted in a reduction in the severity of bunch rot with Optima and a reduction in the incidence and severity with the disease tolerant cultivar Cabernet Franc. The 50% and 100% LR reduced yield per vine by 33% and 46% respectively with Optima and by 32% and 29% respectively with Cabernet Franc. Average berry weight of the 50% and 100% treatments was significantly lower for Cabernet Franc. Within both cultivars, there was no significant effect of treatment on the number of clusters and number of berries per cluster. Significant influence of the treatments on the must and wine quality was also noted.

Influence of Leaf Removal, Fungicide Applications, and Fruit Maturity on Incidence and Severity of Grape Powdery Mildew

Vineyard plots were established in 1988 and 1989 to examine the effects of basal leaf removal, timing of fungicide applications and fruit maturity on incidence and severity of powdery mildew on <i>Vitis vinifera</i> cv. Chardonnay. In plots receiving a single prebloom fungicide application, basal leaf removal reduced disease severity (the percentage of infected fruit per cluster) from 15.3% to 4.2% in 1988 and from 46.1% to 21.0% in 1989. When basal leaf removal was combined with one prebloom and two postbloom fungicide applications in 1988 and three postbloom fungicide applications in 1989, disease incidence (the percentage of infected clusters per vine) and severity was reduced to levels similar to adjacent commercial plots receiving 12 and 11 fungicide applications in 1988 and 1989, respectively. In 1989, significant levels of rachis infection were observed in all plots except those receiving 11 fungicide applications. Healthy fruit removed over the course of the season was inoculated in the laboratory under controlled conditions. A negative exponential relationship was observed between susceptibility of fruit and accumulation of soluble solids, with fruit above 7°Brix rarely infected.

Tomato Leaf Development and Distribution as Influenced by Leaf Removal and Decapitation

The influence of leaf removal and decapitation (removal of apical bud and top two nodes) of determinate tomato (Lycopersicon esculentum Mill cv. Mountain Pride) plants on canopy development was investigated. Leaf removal and decapitation influenced subsequent leaf development and distribution, and early fruiting of greenhouse-grown tomato plants. `Removal of young axillary leaves increased the size of main (true) leaves in the middle and upper nodes, increased the number of nodes, and increased the number of early fruit produced. Removal of main leaves reduced axillary leaf development at nodes 5 and 9. Decapitation increased axillary leaf development in the middle and upper nodes and delayed early fruit production. These results suggest that cultural practices of tomatoes that remove leaves or apical buds to influence fruiting also affect canopy leaf development and distribution.

Influence of leaf removal from the fruit cluster zone on the components of evaporative potential within grapevine canopies

Removal of leaves from around grape clusters reduces development of botrytis bunch rot. In past laboratory experiments, growth of Botrytis cinerea was negatively vffected by evaporative potential, the capacity of air to evaporated water. In the present study removal of leaves around clusters in grapevine canopies increased evaporative potentials significantly over those in canopies in which leaves were not removed. The relationships between evaporative potential and other microclimatic variables were evaluated. Vapor pressure deficits were very similar in grapevine canopies with or without leaves removed from around grape clusters, but wind speed was significantly greater around clusters where leaves were removed. The significant increases in evaporative potential associated with removal of leaves were correlated with increases in wind speeds within canopies. In contrast, the evaporative potential above the vineyard canopy was influenced most strongly by vapor pressure deficit and to a lesser extent by wind speed. Evaporative potentials within vine canopies were predicted accurately by wind speed and vapor pressure deficit using multiple-regression methods. Evaluations of these relationships and their impact on disease should provide insight into possible manipulations of other cropping systems to control disease.

Influence of Leaf Removal, Root Pruning, and Soil Addition on the Growth of Greenhouse-grown Strawberry Plants

Abstract Experiments were conducted to examine strawberry (Fragaria × anannassa Duchesne) plant renovation practices, singly and in combination, for effects on vegetative growth of greenhouse-grown, potted strawberry plants. The major results of these experiments were as follows: a) most of the plants that were both defoliated and root-pruned after fruit harvest died; b) there was a negative linear relationship between the number of leaves removed and the number of new leaves and runners produced; c) root, leaf, and total plant dry weights were negatively correlated with the severity of root pruning; and d) soil addition after fruit harvest decreased the shoot : root ratio of multiple-crown plants, but had no effect on single-crown plants.

The Influence of Leaf Removal upon the Development of the Grain of Winter Wheat

The Influence of Leaf Removal upon the Development of the Grain of Winter Wheat