Changes in the Leaf Area Ratio During Growth of Marquis Wheat, as Affected by Temperature and Light Intensity

Abstract

The increase in the leaf area ratio during early growth and the later decrease were primarily caused by an initial increase in the growth of leaves relative to stems and roots and a later rapid increase in stem growth associated with flowering. Changes in leaf thickness with time had little effect on the leaf area ratio.Increasing temperature from 10 to 25 °C increased the leaf area ratio because the growth of leaves was promoted to a greater extent than the growth of stems and roots, and because leaves were thinner. A further increase in temperature to 30 °C lowered the leaf area ratio because of an increased proportion of stem and thicker leaves.Increasing light intensity from 200 to 2500 ft-c decreased the leaf area ratio because of an increase in the relative proportion of stem and root and increased leaf thickness.These effects of the environment were mostly independent of changes in the rate of development of the plant.

An empirical description of photosynthetic area in wheat crops

“…From further differentiation the maximum rate of foliage production (u,) lies at a time (tJ, given by E + U'E t"= Y - ( 7 ) and the maximum rate of senescence (w,) at a time (t,,,) is given by: Substituting (tu) or (tw) for t in equation (2) u, and w, are found accordingly:…”

“…t"= Y - ( 7 ) and the maximum rate of senescence (w,) at a time (t,,,) is given by: Substituting (tu) or (tw) for t in equation (2) u, and w, are found accordingly:…”

Evaporative cooling of heated irrigation water by sprinkler application

“…Plant tolerance to temperature varies with species, but in most crop plants yields decline at root temperatures of about 30øC and death occurs when temperatures rise above 38 ø [Mil-let, 1938]. Friend et al [1962aFriend et al [ , 1962bFriend et al [ , 1964 studied temperature response in wheat and found that 30øC gave the optimum growth rate but that over the entire growth period the relative growth rate was greatest at 25øC. Thus, where source water exceeds tolerable temperatures, some means of cooling will be required to assure successful usage for crop growth.…”

The influence of temperatures on differentiation of oat genotypes

“…From other investigations. Friend _et (1962aFriend _et ( , 1965 reported that raising the temperature by 5° intervals between 10° and 25° C, caused higher rates of leaf initiation, emergence and expansion, and greater leaf area-stem ratios. In general, Newton (1945) found that 28-day seedlings of spring wheat increased in dry weight with elevated temperature and greater light.…”