Abstract
Cotton plants (Gossypium hirsutum L. cultivar Deltapine 16) were grown at various Ca concentrations (50, 100, 200, and 5,000 uM Ca/1) under different light intensities (6,000; 22,000, and 32,000 lux) to study the influence of the interaction between light and substrate Ca level on growth, Ca accumulation, transpiration, and starch accumulation and translocation. Elemental and starch analyses were conducted on plants grown at the various Ca levels for 14, 28, and 35 days. By 35 days it was evident that growth was influenced by the interaction between light intensity and Ca supply. Plants grown at 50 uM Ca/1 showed a very small increase in dry weight for the first 21 days but by 28 days all plants in that Ca series were dead under all three intensities. Growth of the plants grown at 100 uM Ca/1, however, increased in dry weight from 47% of the controls (5,000 uM Ca/1) at 6,000 lux to 77% of the controls at 32,000 lux. For plants grown at 200 uM Ca/1 a corresponding change from 52% to 90% was observed. Thus, there appears to be at least two substrate threshold levels for Ca. The first can be called an absolute threshold (between 50 and 100 uM Ca/1) which is not influenced by light intensity, and the second can be referred to as a Ca threshold for continued survival which decreases as the light intensity is increased. ...
Gossett, Dalton Ray (1973). The influence of light intensity on the calcium nutrition of cotton. Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -156299.