Quantitative Analysis of Respiration in The Seedling Growth of Summer Forage Crops : I. Growth efficiency in endosperm-dependent seedling growth

Abstract

This study was carried out to make clear the relationship between seedling growth and respiration in summer forage crops. Rhodesgrass (Chrolis gayana KUNTH), African millet (Eleusine coracana GAERTN.), sorghum (Sorghum bicolor (L.) MOENCH.), corn (Zea mays L.) and some comparative crops were investigated under complete dark conditions. The results obtained are summerized as follows ; 1. Seed weight had a strong influence on the reduction rate of endosperm. Species of which seeds were light in weight had higher reduction rate of endosperm (%/day) than that of heavy seed species, and the reduction rate of Rhodesgrass was highest. 2. Reduction rate of endosperm was likely to be related with relative growth rate (RGR). As a whole, species with high reduction rate had higher RGR. The highest RGR was showen in African millet. It was estimated from these results mentioned above that not only reduction rate of endosperm but respiration could couse RGR of summer forage crops in endosperm-dependent seedling growth. 3. Temperature had remarkable effects on the reduction rate of endosperm and RGR, but little effect on the growth efficiency (GE). 4. The specific differences in growth efficiency among summer forage crops were observed, and the value of GE of African millet was higher than that of others. From these results, it was recognized that the high value of GE increased RGR in the seedling growth of African millet.