Interrelationships among various organs of crop plants grown under environmental stresses and their control.

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This research has been conducted in collaboration with crop scientists covering a wide range of specialities, for clarifying the interrelationships among various organs of crop plants, under different environmental stresses. Using several field crops, the experiments were carried out from eco-physiological as well as morphological points of view.1. Throughout the research, many new techniques have been exploited and utilized. That is, methods of measuring root directions and rooting densities, measures of restriction of root spread, a simple method of measuring root respiration and so on.2. The findings observed by these and other methods are as follws:(1) Soil moisture stress in the early growing stages accelerates root growth , thus leading the plant to be more resistant to drought.(2) Deeply spread roots are efficient for the growth of the plant including harvesting organs.(3) Increase in photosynthetic rate stimulates respiration or roots and contributes to the promotion of root activity.(4) Root quantity as well as root activity have great influences on plant growth.(5) The growth hormones produced in roots accelerate plant growth and inhibit the sinescence of leaves.(6) The interrelationships mentioned above varies in accordance with different crop species and cultivars used.3. The results obtained in this research may open a promising way for understanding the crop plants as a whole and for clarifying the most difficult problems existing between form and function of crop plants growing under different environmental conditions. It is expected that more extensive researchis will develop along the way thus explored.