云锦杜鹃种子萌发及对干旱胁迫的响应

以不同渗透势的PEG-6000溶液模拟干旱胁迫条件, 研究云锦杜鹃种子的萌发、幼苗生长和累积吸水率对干旱胁迫的响应。结果显示：种子于第14 d开始萌发,萌发期为8 d,总萌发率为45.5%±1.7%。在渗透势为-0.3～-0.6 MPa的溶液中, 种子的累计吸水率在第5 d就超过对照(蒸馏水中), 种子的萌发和幼苗的生长也优于对照, 说明云锦杜鹃种子不适合过于湿润的土壤环境中萌发。但溶液的渗透势≥-0.9 MPa时, 种子的吸水减缓、萌发率下降, 同时幼苗的生长也慢, 而当渗透势≥-1.8 MPa时, 种子不能充分吸涨、萌发, 说明云锦杜鹃种子对干旱胁迫比较敏感。另外, 经PEG溶液浸种2天后移入蒸馏水中,萌发率均有一定程度的提高, 其中经-0.3～-1.5 MPa的PEG溶液浸种后, 萌发率显著高于对照。提示用一定浓度范围的PEG溶液浸种可使休眠种子活化, 提高种子繁育的效率。

Response of seed germination of Rhododendron fortunei to drought stress

The seed germination, seedling growth and water absorption characteristic of Rhododendron fortunei were investigated under different osmotic potentials (PEG-6000, -0.3~-2.4 MPa) solution. The results were as follows: The seed in distilled water begin germinate from the fourteenth day and last for eight days got a total germination rate with 45.5%±1.7%. The water absorption rate of seeds under -0.3~-0.6 MPa solution was higher than in distilled water after the fifth day. The seed germination and seedling growth were better than in distilled water. The water absorption, seed germination and seedling growth were slow under the osmotic potentials solution ≥-0.9 MPa, and the seed did not imbibe and germinate under the osmotic potentials solution ≥-1.8 MPa. All the results showed that the seed germination and seedling growth were neither the moisture content of soil nor drought environmental conditions. The seed, after 48 hours, treatment with PEG of -0.3～-1.5 MPa, got a higher germination rate, which is significant when compared with the control, and the highest is in the PEG of -0.9 MPa, 57.5%. These work show that the seed was revivified with the treatment of a certain concentration of PEG and got a high efficiency of seed breeding.