A Chlorophyll B Deficient Mutant of Wheat with an Altered Photoadaptation Response

Abstract

Chloroplasts of higher plants and algae are not static structures, but respond to varying environmental conditions with a high degree of plasticity. Variation is seen not only between sun and shade adapted plant species, but also within a single species grown under light regimes differing in quality and quantity (1,2). This process of photoadaptation, which results in maximal photosynthetic efficiency for a given light regime, involves both short term regulatory mechanisms, such as the state1-state2 transition, and long term alterations in thylakoid membrane structure, composition, and function. In general, high light-adapted plants show decreased thylakoid stacking, decreased photosynthetic unit sizes, increased chl a/b ratios, and higher maximal rates of photosynthetic electron transport than do low light-adapted plants.