Comparative Water Relations, Photosynthesis, and Growth of Soybean (Glycine max) and Seven Associated Weeds

Weed Science ◽  
1983 ◽  
Vol 31 (3) ◽  
pp. 318-323 ◽  
Author(s):  
David T. Patterson ◽  
Elizabeth P. Flint

Growth dynamics, water relations, and photosynthesis of soybean [Glycine max(L.) Merr. ‘Ransom’], common cocklebur (Xanthium pensylvanicumWallr.), jimsonweed (Datura stramoniumL.), prickly sida (Sida spinosaL.), sicklepod (Cassia obtusifoliaL.), smooth pigweed (Amaranthus hybridusL.), spurred anoda [Anoda cristata(L.) Schlect.], and velvetleaf (Abutilon theophrastiMedic.) were compared in a controlled-environment greenhouse programmed for 32C day and 23C night temperatures. Net photosynthetic rates, net assimilation rates, and water-use efficiency on a whole-plant or single-leaf basis were greatest in the C4-plant, smooth pigweed. Total dry-matter production at 29 days after planting was greatest in common cocklebur and least in jimsonweed. Interspecific differences in dry-matter production were highly positively correlated with leaf area duration and negatively correlated with net assimilation rate. Threshold leaf water-potential levels causing stomatal closure varied among species. The stomata of jimsonweed were the most sensitive to water stress and those of prickly sida were the least sensitive.

Weed Science ◽  
1983 ◽  
Vol 31 (2) ◽  
pp. 193-199 ◽  
Author(s):  
Elizabeth P. Flint ◽  
David T. Patterson

Effects of temperature and interference were examined in a replacement series experiment with soybean [Glycine max(L.) Merr. ‘Ransom’], common cocklebur (Xanthium pensylvanicumWallr.), and smooth pigweed (Amaranthus hybridusL.). Plants were grown in controlled-environment greenhouses at day/night temperatures of 32/23, 29/20, or 26/17C and harvested 14 and 34 days after planting. In all species, height, dry weight, and leaf area at both harvests, and dry matter and leaf area duration for the harvest interval, increased significantly with temperature. Net assimilation rate in all species peaked at 29/20C. Dry weight and leaf area at day 34, and dry matter production and leaf area duration for the harvest interval, were reduced in plants subjected to interference. Temperature modified the effects of interference upon growth in smooth pigweed, but not in the other species. Common cocklebur and soybean were roughly equivalent as competitors at all temperatures and were superior to smooth pigweed.


1967 ◽  
Vol 45 (11) ◽  
pp. 2063-2072 ◽  
Author(s):  
Holger Brix

Seedlings of Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) were grown in growth chambers under all combinations of three temperatures (13, 18, and 24 °C) and three light intensities (450, 1000, and 1800 ft-c). Dry matter production of leaves, stem, and roots was determined at 65 and 100 days after germination. The leaf area produced per unit of leaf dry weight and the dry matter distribution to the plant organs was measured. Net assimilation rates between the ages of 65 and 100 days were calculated. Rates of photosynthesis per unit of leaf were determined at different light intensities and temperatures, and rates of respiration of plant top and of roots were found for different temperatures.Increasing light intensity affected dry matter production in two opposing ways: (i) it increased the rate of photosynthesis per unit leaf area, and (ii) it decreased the leaf area added per unit of dry matter produced. A pronounced increase in growth with increase in temperature from 13 to 18 °C was a result of a temperature influence on production of leaf area rather than the effect of photosynthesis per unit of leaf. Net assimilation rates decreased with increase in temperature at all light intensities.


1972 ◽  
Vol 8 (4) ◽  
pp. 347-353 ◽  
Author(s):  
R. H. V. Corley ◽  
C. K. Mok

SUMMARYPotassium application appeared to increase dry matter production and yield of oil palms, primarily by increasing leaf area, while nitrogen increased both leaf area and net assimilation rate. Responses to phosphorus and magnesium were harder to interpret. Production of vegetative dry matter attained a fairly constant level at the higher rates of fertilizer application, while the ratio of bunch yield to total dry matter production was little affected by fertilizer treatments. The importance of these results for oil palm breeding, and their possible value in diagnosing fertilizer requirements, are briefly discussed.


Weed Science ◽  
1981 ◽  
Vol 29 (1) ◽  
pp. 53-59 ◽  
Author(s):  
D. T. Patterson

The effects of caffeic acid, chlorogenic acid,t-cinnamic acid,p-coumaric acid, ferulic acid, gallic acid,p-hydroxybenzaldehyde, 5-sulfosalicylic acid, vanillic acid, and vanillin on growth, photosynthesis, water relations, and chlorophyll content of 3-week-old soybeans [Glycine max(L.) Merr. ‘Tracy’] grown in aerated nutrient solution were determined. At concentrations of 10−3M, caffeic,t-cinnamic,p-coumaric, ferulic, gallic, and vanillic acids significantly reduced dry matter production, leaf expansion, height, leaf production, net assimilation rate (rate of dry matter production per unit leaf area), and leaf area duration (total leaf area present during treatment interval). Chlorogenic acid,p-hydroxybenzaldehyde, 5-sulfosalicylic acid, and vanillin at 10−3M did not inhibit growth. None of the 10 compounds at 10−4M inhibited growth. At concentrations of 10−3M, caffeic,t-cinnamic,p-coumaric, ferulic, gallic, and vanillic acids severely reduced net photosynthetic rate and stomatal conductance of single, fully expanded leaves. These same compounds also caused marked reductions in leaf chlorophyll content, with net losses of chlorophyll occurring over an 86-h period after treatment.


1989 ◽  
Vol 10 (1) ◽  
Author(s):  
V. Rajagopal ◽  
A. Ramadasan ◽  
K.V. Kasturibai ◽  
D. Balasimha

Weed Science ◽  
1982 ◽  
Vol 30 (1) ◽  
pp. 25-30 ◽  
Author(s):  
David T. Patterson

The effects of shade on dry-matter production, leaf area, and biomass partitioning in purple nutsedge (Cyperus rotundusL.) and yellow nutsedge (C. esculentusL.) were determined in a controlled-environment greenhouse with a day/night temperature regime of 32/26 C. For comparison with a full-light treatment, screening provided 40, 70, and 85% shade. Shading significantly reduced height of yellow nutsedge and dry-matter production, leaf-area production, and rhizome and tuber formation of both species. Shading decreased the partitioning of plant biomass into tubers and rhizomes and increased partitioning into leaves. Yellow nutsedge had a higher net-assimilation rate than purple nutsedge at all levels of shading, but the greater leaf-area duration or total amount of leaf area present in purple nutsedge resulted in greater dry-matter production by that species. The responses of the two species showed no differences in shade tolerance.


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