scholarly journals Photosynthetic Compensation to Partial Leaf Area Reduction in Sour Cherry

1992 ◽  
Vol 117 (2) ◽  
pp. 279-286 ◽  
Author(s):  
Desmond R. Layne ◽  
J.A. Flore

The leaf surface area of l-year-old, potted `Montmorency' sour cherry (Prunus cerasus L.) trees was reduced by punching disks from some or all leaves to determine the threshold level of leaf area removal (LAR) necessary to reduce net CO2 assimilation (A) and whole-plant growth. Removal of 30% of the leaf area of individual leaves reduced A on a whole-leaf basis between 1 and 3 weeks following LAR. Less than 30% LAR was compensated for by higher estimated carboxylation efficiency and ribulose-l,5-bisphosphate (RuBP) regeneration capacity. The threshold level of LAR based on gas exchange of individual leaves was 20%. Although whole-plant dry weight accumulation was reduced at all levels of LAR, a disproportionately large decrease in dry weight occurred as LAR increased from 20% to 30%. This result indicates that 30% LAR exceeded the threshold LAR level that was noted for A (20% LAR). Wound ethylene production induced by leaf-punching ceased after 24 hours, which indicated that wounds had healed and that ethylene, therefore, did not influence A significantly. The observed threshoId of 20% LAR represents a significant compensation ability for sour cherry, but this threshold may change with crop load, environment, or both.

1972 ◽  
Vol 2 (2) ◽  
pp. 98-104 ◽  
Author(s):  
Philip R. Larson ◽  
J. G. Isebrands

The relationship between leaf production and wood production in two clones of Populus grown for 1 year under intensive culture was investigated. Wood weight at any one stem position was highly correlated with the cumulative leaf area above that position. About one-half the total stem weight was bark, but the bark/wood ratio decreased with increasing leaf area. Wood specific gravity in creased from stem top to stem base, with mid-stem values of about 0.35. Leaf surface area and leaf dry weight were highly correlated with leaf lamina length; the latter therefore provides an easily measured, non-destructive estimate of photosynthesizing leaf surface. Marked clonal differences existed in all parameters measured.


1996 ◽  
Vol 121 (1) ◽  
pp. 69-76 ◽  
Author(s):  
Ursula Schuch ◽  
Richard A. Redak ◽  
James Bethke

Six cultivars of poinsettia (Euphorbia pulcherrima Wind.), `Angelika White', `Celebrate 2', `Freedom Red', `Lilo Red', `Red Sails', and `Supjibi Red' were grown for 9 weeks during vegetative development under three constant-feed fertilizer treatments, 80,160, or 240 mg N/liter and two irrigation regimes, well-watered (high irrigation) or water deficient (low irrigation). Plants fertilized with 80 or 240 mg N/liter were 10% to 18% shorter, while those fertilized with 160 mg N/liter were 25 % shorter with low versus high irrigation. Leaf area and leaf dry weight increased linearly in response to increasing fertilizer concentrations. Low irrigation reduced leaf area, leaf, stem, and shoot dry weight 3670 to 41%. Cultivars responded similarly to irrigation and fertilizer treatments in all components of shoot biomass production and no interactions between the main effects and cultivars occurred. Stomatal conductance and transpiration decreased with increasing fertilizer rates or sometimes with low irrigation. Highest chlorophyll contents occurred in leaves of `Lilo Red' and `Freedom Red'. Leaves of plants fertilized with 80 mg N/liter were deficient in leaf N and had 40 % to 49 % lower leaf chlorophyll content compared to plants fertilized with 160 or 240 mg N/liter. Irrigation had no effect on leaf N or chlorophyll content. At the end of the experiment leaves of `Supjibi Red' and `Angelika White' contained higher concentrations of soluble proteins than the other four cultivars.


Weed Science ◽  
1978 ◽  
Vol 26 (1) ◽  
pp. 51-57 ◽  
Author(s):  
M. B. Awang ◽  
T. J. Monaco

Germination studies on camphorweed [Heterotheca subaxillaris(Lam.) Britt. & Rusby] revealed that freshly harvested disk achenes germinated best at 17.5 C (88%) while ray achenes were dormant. Camphorweed seed from disk achenes also germinated at temperatures as low as 3 C. Seedlings grown under long-day conditions at 23 C day and 8 C night temperatures for 144 days elongated at the rate of 0.18 cm/day. Plants grown under short-day conditions at the same temperature regime elongated at the rate of 0.06 cm/day. Total leaf surface area, fresh weight, and dry weight of shoots of plants grown under long days were at least 1.5 times greater than plants grown under short day conditions. Camphorweed, regardless of size and age, survived a 2-h exposure at −5 C. All plants in the rosette stage survived at −15 C in the freezer and an overnight temperature of −11.7 C in the field, whereas larger plants were killed at these temperatures. Stage of growth was an important factor in the herbicidal control of camphorweed. Plants in the rosette stage were generally more susceptible to herbicides than older plants. Simazine [2-chloro-4,6-bis(ethylamino)-s-triazine] at 3.4 kg/ha, paraquat (1,1′-dimethyl-4,4′-bypyridinium ion) at 0.6 kg/ha, methazole [2-(3,4-dichlorophenyl)-4-methyl-1,2,4-oxadiazolidine-3,5-dione] at 5.0 kg/ha, and a formulated mix of diuron [3–3,4-dichlorophenyl)-1,1-dimethylurea] and terbacil (3-tert-butyl-5-chloro-6-methyluracil) at 4.5 kg/ha provided adequate control of camphorweed in the rosette stage. Asulam (methyl sulfanilylcarbamate) at 2.2 or 4.5 kg/ha applied alone did not control camphorweed in the rosette form but was more effective on older plants. Various combinations of these herbicides were generally effective at both stages of growth.


1991 ◽  
Vol 21 (7) ◽  
pp. 1043-1048 ◽  
Author(s):  
T. E. Kolb ◽  
D. A. J. Teulon

The relationship between budburst phenology and damage by the pear thrips (Taeniothripsinconsequens (Uzel) (Thysanoptera: Thripidae)) to sugar maple (Acersaccharum Marsh.) foliage was investigated in two studies. In the first study, seedlings in cages were exposed to adult thrips at different stages of budburst. Compared with uninfested control seedlings, introduction of five adult thrips per bud reduced total leaf area and average leaf size, and caused chlorosis, tattering, and cupping of leaves. Leaf area reduction and damage symptoms were greater for seedlings exposed to thrips when leaf margins were first visible at the tip of the bud compared with earlier and later stages of budburst. In the second study, budburst date and number of thrips oviposition sites on leaves (an index of thrips activity) were measured in a common-garden test of maple saplings from open-pollinated families. Thrips activity was greater on early-breaking than late-breaking buds. Date of opening for these early-breaking buds coincided closely with peak capture of flying thrips. Both budburst date and number of oviposition sites on leaves differed among families. Sugar maple genotypes with late budburst escaped heavy thrips damage. The results indicate that timing of vegetative budburst in sugar maple can influence the degree of thrips damage.


2009 ◽  
Vol 55 (No. 5) ◽  
pp. 181-186 ◽  
Author(s):  
R. Cerkal ◽  
K. Vejražka ◽  
J. Kamler ◽  
J. Dvořák

This work presents the results of a survey that studied simulated plant browsing by herbivores. In 2004–2006, winter wheat, spring barley, and maize field trials were founded in order to monitor the impact of different levels of defoliation (leaf area reduction) on the yield and grain quality. The defoliation was carried out by means of mechanical removal of plant parts in the early growth stages. Selected qualitative parameters were determined in the harvested grain of wheat and barley. Statistically significant influence of leaf area reduction (LAR) on grain yield (decrease by 4–14%) was found only in maize in 2004. No statistically significant influence of the leaf area reduction on thousand grain weight (TGW) was found in any of the studied crops. The leaf area reduction in barley did not affect grain characteristics; however, it had a statistically significant influence on the quality of wheat grain. Moreover, wheat reduction statistically significantly increased the falling number (by 29–39 s) and decreased SDS test values (by 8–9 ml).


HortScience ◽  
1990 ◽  
Vol 25 (12) ◽  
pp. 1578-1581 ◽  
Author(s):  
Curt R. Rom ◽  
Bruce Barritt

The role of spur leaves in bud and fruit development on two spur-type `Delicious' apple strains (Malus domestica Borkh.) and factors affecting spur development were studied. Reducing spur leaf area on vegetative spurs in August reduced the number of spurs that flowered the following year but did not affect flower size. On spurs that did flower, leaf area reduction the previous year did not influence leaf number or area, but the bourse shoot leaf area was reduced. Spur bud diameter, leaf area, size, specific leaf weight (SLW), and leaf dry weight were larger on 2-year-old vegetative spurs than on 1- or 3-year-old spurs. Within each age section of a limb, spur leaf number, area, size, SLW, and bud diameter decreased from the apical to basal positions on the limb. Flower number did not vary within a limb section, but fruit set was lower on the most apical and basal spurs compared to midshoot spurs. Fruit size was largest at the apical end of each limb section and was smallest at basal positions. These relationships were not affected by strain, tree age, or orchard location. Summer pruning at 30 days after bloom tended to increase leaf number, area, size, and spur length compared to unpruned trees or pruning later in the season but did not influence spur bud diameter.


HortScience ◽  
1991 ◽  
Vol 26 (9) ◽  
pp. 1142-1145 ◽  
Author(s):  
Eric J. Hanson

Seven trials were conducted over 3 years in several Michigan locations to study the response of sour cherry (Prunus cerasus L. cv. Montmorency) to foliar B sprays. Orchards ranged in age (6 to 12 years) and leaf B concentrations (19 to 32 μg B/g dry weight). Treatments consisted of a 500 mg B/liter spray applied to leaves in late September or early October, and an untreated control. Boron sprays increased B concentrations in dormant buds and flowers by 94% and 54%, respectively, but did not consistently change leaf levels. Boron applications increased fruit set and production by as much as 100% in one trial, but had no effect in others. Fruit set and production were most consistently increased in trees containing leaf B levels of 19 to 25 μg·g–1 dry weight. In trees with leaf B concentrations of 25 to 32 μg·g–1, responses to B were less consistent and smaller in magnitude.


Author(s):  
Patrik BURG ◽  
Jana BURGOVÁ ◽  
Vladimír MAŠÁN ◽  
Miroslav VACHŮN

Experimental measurements focused on evaluation of grapevine leaf surface area development in nine varieties, in the viticultural conditions of South Moravia. The dynamics of leaf surface area development was measured by using a device called leaf area meter AM 300. The device operates on the principle of a scanner and the resulting values are expressed through the leaf area index - LAI. The measurements were carried out in five dates during phenophases of growth, flowering, initial development of fruits, and ripening of berries. The results show a significant differences in increase in leaf area between the evaluated varieties, especially during flowering. The size of the leaf area, depending on the year, corresponds to values between 7.615 and 13.483 square metres per hectare. The largest leaf area was reached in growth stage 8, which is ripening of fruit. The leaf area reached the largest size in the varieties Grüner Veltliner, Zweigelt, and Sauvignon, with values ranging from 20.560 to 26.481 square metres per hectare. The results suggest that a significant proportion of leaf area is also represented by lateral shoots whose size in the ripening phase, depending on variety, ranges from 33.7 to 52.9 per cent of the total leaf area.


Author(s):  
O.V. Nikitenko ◽  
S.V. Litoshko

As a result of the conducted in 2016–2018 studies on the study of the features of photosynthetic activity of the Ratnik hybrid sunflower found that the indicators of the leaf area of one plant and one hectare changed under the influence of the use of mineral fertilizers and growth regulators and were large according to the classical system of basic tillage. The largest indices of the leaf surface area of one plant in all systems of basic tillage were noted with the introduction of full fertilizer N60P60K60. The use of growth regulators in all combinations resulted in an increase in leaf area per plant and per hectare. Large indices of net productivity of photosynthesis were noted in crops according to the classical system of basic tillage, which were, depending on the scheme of drug use: on the control (without fertilizers) – 5,95–6,16 g/m2 × day, in variants with the introduction of N40 – 6,31–6,56 g/m2 × day, in variants with the introduction of N40P60 – 6,25–6,47 g/m2 × day in the variants with the introduction of N60P60K60 – 6,29–6,42 g/m2 × day. The application of mineral fertilizers in various doses contributed to an increase in the net productivity of photosynthesis: according to the classical system by 0,31–0,44, according to the moldboard-free system by 0,02–0,24, at the minimum 0,01–0,08 g/m2 × day. The most favorable conditions for the formation of productivity by sunflower plants have developed according to the classical system of basic tillage with a yield depending on the dose of fertilizers and the option of using growth regulators 2,62–3,46 t/ha. The highest yields of the Ratnik hybrid sunflower – 3.46 and 3.45 t/ha, were obtained when growing according to the classical system of basic tillage, applying mineral fertilizers in a dose of N60P60K60 for pre-sowing cultivation of the second and fifth options for using growth regulators: 2. Rost-concentrate + Chelatin oilseeds (6–8 pairs of real leaves) 5.1 processing: Chelatin phosphorus-potassium + Chelatin мultimix + Chelatin mono boron (3–4 pairs of real leaves), 2 processing: Chelatin mono boron (6–8 pairs of real leaves). The formation of the crop was largely influenced by the system of basic tillage (r = -0.66) and the use of mineral fertilizers (r = 0.61) and the weak use of drugs (r = 0.17). It should be noted the close relationship between yield and leaf surface area (r = 0.78), CPF (r = 0.78), dry matter weight per plant (r = 0.99) and seed weight (r = 0.97 ). Key words: sunflower, system of basic tillage, mineral fertilizer, growth regulator, leaf area, net productivity of photosynthesis, yield.


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