Relationships of Soil Moisture Stress to Different Aspects of Growth in Ladino Clover

Abstract

The relationships of soil moisture content or soil moisture stress to growth in Ladino clover have been investigated in containers under controlled environmental conditions and in field plots. Relationships involving the following aspects of growth or plant functioning are reported: (1) transpiration rate, (2) green weight production, (3) dry weight production, (4) dry matter percentage, (5) shoot elongation, (6) photosynthesis rate, (7) respiration rate, (8) chemical composition, (9) flower formation (number and size), and (10) seed production. Dry weight production of vegetative material, photosynthesis, and respiration rates were not affected appreciably until the moisture content in the entire root zone approached the permanent wilting percentage. Green weight production and shoot elongation were reduced significantly when the soil moisture content fell into the lower half of the available range. Chemical composition, flower formation, and seed production were also influenced by moisture conditions within the available range. The different relationships obtained illustrate that the increasing soil moisture stress experienced by Ladino clover as the readily available moisture is depleted does not have a uniform effect upon various aspects of its functioning and growth. Thus there is no one simple and general relation between soil moisture conditions and all aspects of plant functioning. Some plant processes are relatively insensitive to increasing moisture stress over the available range while others are distinctly affected. Such soil moisture‐growth relationships are also dependent upon plant characteristics, soil conditions, and climatic factors. Information on these relationships should suggest opportunities for more effective irrigation by considering both the soil moisture stress and the physiological stage of plant development in the timing of water applications.

Effect of Moisture Supply upon Translocation and Storage of 14C in Sugarcane

“…Photosynthesis, as measuired by total activity in the plant after traiislocation for 90 minuttes (thus before much differential couild be catused by respiration), decreased 18 % in each of the plants with low moistuire suipply (fig 1). This decrease is in agreement with previously reported results on photosynthesis in sugarcane (1,7,8,9,15) andl in other plants (6,24,28,31,32,38). Whereas total fixation decreased 18 %, translocation from the same leaves decreased 93 % at 4.4 atm and 94 % at 6.4 atm (fig 1).…”

Effect of closing date and irrigation on seed yield (and some yield components) of ‘Grasslands Kopu’ white clover

“…The lack of an effect of closing date on seed numbers per inflorescence shows that closing date per se had no major effect on ovule abortion rates. This finding implies that ovule abortion is more closely associated with limitation of photosynthesis by moisture stress (Hagan et al 1957). In my study, irrigation, regardless of closing date, increased seed numbers per inflorescence by 23%.…”

“…Hagan et al (1957) found that, for ladino white clover, most inflorescences were formed when soil moisture available to plants was maintained at 25%. Rate of photosynthesis was appreciably reduced only when plants reached permanent wilting point.…”

Protein, Nucleotide, & Ribonucleid Acid Metabolism in Corn During Germination Under Water Stress

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While the influence of sub-optimal water levels on gross aspects of plant growth has been investigated extensively (3,5,6,13,19), little is known about the effect of water stress on metabolic processes. More information on specific effects is needed to establish the influence of environmental-water stress on plant growth and development.

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