【摘要】 <正> 绿萍具有较强的光合固氮作用,在中国早已广泛养殖,用作稻田绿肥和畜禽饲料。对于绿萍属的各个种,尚未有集中在一起同时比较鉴定其农业利用性质。本研究是将分布在世界五大洲的8个绿萍种的若干样品,经初步比较后选取其中12个品系,进行全年繁殖,并对固氮活性、肥分含量,抗逆性能等农业利用性质进行考察,为农业生产选取新的绿萍种源。更多还原

【Abstract】 12 specimens have been chosen from 8 Azolla species (A. irnbricata, A.filiculoides) A. microphylla, A. caraliniana, A. mexicana, A. Pinnata, A. nilotica, A. rubra) which were introduced from various continents of the world.An experiment has been recently finished for these Azolla specimens about their utilization properties in agriculture, namely, the annual propagation rate, N-fixing capacity, endurance to adversity, fertility and nutrient contents.There are positive relationships between the propagation rate, nutrient content and N-fixing capacity for all the Azolla specimens. This phenomenon may be reinted to the temperature sensitivity of Azolla, 4 out of the 8 species of Azolla being of the temperature-sensitive type. It has been observed that for different species of Azolla in the same growing period (or in the most favourable period of growth for each species of Azolla) there existed significant differences in the propagating rate and the N-fixing capacity. For example, the difference in the amount of annual N accumulation is as great as 65—255 jin/mu with the A. imbricata (No.11), A. caroliniana, A. microphylla, and A.filiculoides.The N-fixing capacity of Azolla is very sensitively influenced by the variation in light intensity. For all species of Azolla the N-fixation ability remains in function during the whole day and night, but the capacity during night is only about 25—30% of that during the day.更多还原