Yield and Environmental Stress

Abstract

Plant development is affected by physical stresses of all kinds. The most sensitive time is during anthesis and early fruit growth, when reproductive structures may fail to develop or embryos may abort. Water limitation can cause both effects, and explanatory theories are based on turgor, photosynthate availability, or hormonal relationships. Data will be presented for maize to show that failure of the female flower accounts for reproductive sensitivity to limited water. There is a correlation between sensitivity and the availability of reserve photosynthate that overrides the effects of turgor. The failure of the female flower is attributable partly to inhibited silk growth and partly to arrested development of the entire seed after fertilization takes place.