Studies of "Excess-Moisture Injury" in Rape Plants : On the Varietal Difference in Oxygen Consumption

Abstract

1. Experiments wer conducted to know about the varietal difference in the resistance of rape plants to excess-moisture injury. 2. Three varieties, Namely Norin-15, Norin-16 and Norin-3, were used. as materials. Three hundred seedlings of each variety, very young and their cotyledons, just having opened, were transplanted into four vessels covered with water, and their oxygen consumption in water was measured with Winkler's method. 3. a) The oxygen consumption in Norin-15 was higer than in Norin-16 in the earlier period of submergence while in the later perid the consumption in the latter became higher steadily till, at last, the relation became inverse. (See to Fig. 1) b) Consumption in the roots alone indicated the similar tendency as mentioned above, but the the procession of consumption was prolonged in both the two varieties (Fig. 3) c) When oxygen dissoled in water was scanty, the point where the oxygen consumption became equal between the two varieties was reached ealier than in the case a, and oxygen was consumed rapidly. (See to Fig. 4) d) The uptake of water by the tissues of cotyledons proceeded as shown in Fig 2, namely the quantity of mater uptaken in Norin-15 was the largest of the three varieties. e) Norin-3 was the next to Norin-15 in the intensity of water uptake. 4. Form the results mentioned above, it is clear that there is a difference in oxygen consumption between Norin-16 and Norin-15. According to general idea that the respiration in varieties sensitive against excess-moisture injury would be more active than in resistive ones, Norin-16 may be more resistive than Norin-15. Only a later stage of submergence treatment, the respiration of Norin-15 decreased because of the weakning of plants, and accordingly the resistance of the variety to excess-moisture injury was stronger. 5. We shall consider the respiration of plants of normal growth and the oxygen consumption abnormal growth under oxygen deficiency. 6. Any reasonable relation is found in gas metabolism of plants would not be explained without regulation of the environmental conditions under which they grow.