抄録
Propagated plants of a clone from orchardgrass, cv. Frode, were grown outdoors under short-day condition by solution culture method. The temperature of culture solution before or after cutting was maintained at 10°, 17°, 24°and/or 30°C, respectively, under natural air temperature condition (Table 1). The results are summarized as follows. 1. There were differences in growth resulting from variation in the root temperature during 10 days before cutting (Table 2). Dry weight of top and root was highest at 17°C of root temperature, lowest at 30°C except for the case where the weight was lowest at 10°C under the highest air temperature condition. Carbohydrate content in the stubble became higher with decrease of root temperature except for the case where air temperature was highest. 2. Dry weight of regrowth portion (Fig. 1) and basal part of top (Fig. 4), leaf area (Fig. 2), number of tillers (Fig. 3) and dry weight of root (Fig. 5) were highest at 10°C or 17°C of root temperature before cutting except for the case of highest air temperature condition and lowest at 30°C. Carbohydrate content in the basal part of top became higher with increase of the root temperature before cutting when air temperature was low (Fig. 6). 3. Dry weight of regrowth portion 12 days after cutting was highest at 10°C or 17°C of root temperature after cutting except for the case where air temperature was lowest (Fig. 1). The one 25 days after cutting was highest at 17°C, lowest at 30°C. Leaf area (Fig. 2), number of tillers (Fig. 3) and dry weight of basal part of top (Fig. 4) and root (Fig. 5) 25 days after cutting showed the same trend as the one in regrowth. Carbohydrate content in the basal part of top (Fig. 6) was high in plants of heavy dry weight of the part. It is suggested from these results that growth of non-cut plants and of plants elapsed some days after cutting are accelerated at 17°C of root temperature and restricted at 30°C. It is also suggested that the optimum root temperature just before or just after cutting for the regrowth is 10°C to 17°C.
