【摘要】 种子萌发及幼苗光合实验的结果表明 ,旱冬瓜种子具有需光萌发的特性 ,黑暗中即使种子处在适于萌发的温度和水分条件下 ,种子仍保持休眠状态 ,需接受光照刺激才能解除休眠而萌发 ,故播种育苗时种子不宜盖土。旱冬瓜幼苗生长的初期光补偿点为 12 μmol/m2 s,光饱和点为 10 0 0 μmol/m2 s,具有一定的耐阴能力 ,适宜在5 0 %遮荫条件下生长。随着月龄的增加 ,耐阴能力下降。 6月龄苗光合补偿点上升到 2 1μmol/m2 s,光饱和点超过 2 0 0 0 μmol/m2 s ,只有在全光照的条件下才能生长良好 ,遮荫会降低幼苗高生长量和基径粗生长量。晴天 ,旱冬瓜幼苗光合作用存在“午睡现象” ,当植株处于缺水状态时 ,光合作用的“午睡现象”会更加强烈。表明旱冬瓜适宜种植在次生裸地或撂荒地 ,种植后应及时除草进行透光抚育。更多还原

【Abstract】 The results of seed germination and photosynthesis determination showed that Alnus nepalensis seed was positive blastic seed, therefore it is not proper to cover the seeds with soil while seeding. The initial stage light compensation point of A nepalensis was 12 μmol/m 2 s, and the light saturation point was 1 000 μmol/m 2 s, which indicated that the seedling of this species was tolerant to shade at initial stage and adapted to grow in shade of 50 % of full light. The capability of shade tolerance would decrease with the growing of the seedling. Up to the age of six months, the light compensation point attained 21 μmol/m 2 s, and the light compensation point was over 2 000 μmol/m 2 s, seedling could only grow well under full light, whereas shade would decrease the growth of both height and diameter at ground. In sunny day, the midday depression of photosynthesis was observed at noon, when the plant was deficit of water, the midday depression of photosynthesis would increase. It was suggested A neplanensis at secondary bare land or fallow land, weeding and light were very important tending measures.更多还原