Plant and Cell Physiology · 1985 · 67 citations · 0 references
Life SciencesPlant BiologyPlant SciencesPhotosynthesisPlant BiochemistryPlant PhysiologyChloroplast BiochemistryChloroplast BiologyChloroplast StructureChloroplast UltrastructureHeat Stress PhysiologyThylakoid Membrane StructureChloroplast Ultrastructural Responses To StressChloroplast Ultrastructural Responses To TemperatureChloroplast Ultrastructure AlterationHeat Stress Effects On PhotosynthesisPhotosynthetic ControlPhotosynthetic PhysiologyPhotosynthetic ProductivityPlant Heat Stress Physiology
The effect of heat stress (47.5°C for 2 min given to the roots) on photosynthetic activity and chloroplast ultrastructure was studied in correlation with the endogenous cytokinin concentration in maize (Zea mays L. “Fronica”) seedlings. Shoot and root growth were visibly inhibited by the heat treatment. In etiolated leaf segments there was a clear-cut inhibition of photosynthetic activity, chlorophyll accumulation and chloroplast development. This inhibition was reversible by benzyladenine. In green tissue heat stress only affected photosynthetic activity and chlorophyll accumulation. Again this inhibition could be reversed by benzyladenine. In the primary leaves of green seedlings heat stress lowered cytokinin concentration severely; in etiolated leaves no effect of heat stress could be observed, since the cytokinin concentration was below the detectable level. Our results provide an indication for a correlation between hormonal control and chloroplast biogenesis.