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测定了适宜温度和光照条件下胡杨(Populus euphratica)种子萌发及胚生长对盐胁迫和干旱胁迫的响应。结果表明:(1)胡杨种子萌发的最佳条件是25℃/30℃和12h光照/12h黑暗的温光组合。光照虽然影响胚根的生长、抑制胚轴的伸长,但有利于子叶长度的增加和子叶叶绿素的合成。低温(10℃/15℃、15℃/20℃)和高温(35℃/40℃)不利于胚根的伸长和子叶生长;黑暗条件下温度显著影响胚轴生长。(2)不同渗透势溶液对胡杨种子萌发后子叶的展开和胚根的生长影响较大。当溶液渗透势在-0.2~0 MPa时,胚的生长不受影响;而渗透势低于-0.2 MPa,下胚轴、胚根和子叶的生长都受到抑制,尤其当溶液渗透势低于-0.6 MPa时,子叶的展开也受到影响。-0.2 MPa是胡杨胚生长的一个临界渗透势。(3)胚根、子叶生长对NaCl胁迫比较敏感,表现为种子在0~0.80mol·L-1 NaCl溶液浓度范围内可以萌发,但胚根和子叶的生长在0.05mol·L-1浓度时与对照存在显著差异;在溶液浓度大于0.10mol·L-1时子叶出现黄化现象;而在0.20~0.80mol·L-1范围内子叶则不能正常展开。胡杨种子快速集中地萌发,是对干旱少雨环境的一种适应;而萌发后水、盐胁迫对胡杨胚生长的影响,是限制胡杨实生繁殖成功的关键。
The responses of Populus euphratica seed germination and embryo growth to salt and drought stress under suitable temperature and light were measured. The results showed that: (1) The optimum conditions for poplar seeds germination were 25 ℃ / 30 ℃ and 12 h light / 12 h dark light and light combinations. Although light affects radicle growth and inhibits elongation of hypocotyls, it is beneficial to increase cotyledon length and cotyledon chlorophyll synthesis. Low temperature (10 ° C / 15 ° C, 15 ° C / 20 ° C) and high temperature (35 ° C / 40 ° C) are detrimental to radicle elongation and cotyledon growth; darkness significantly affects growth of hypocotyls. (2) Different osmotic potential solutions have a great influence on the development of cotyledon and the growth of radicle after the germination of Populus euphratica seeds. The growth of embryos was not affected when the osmotic potential was between -0.2 and 0 MPa. However, the osmotic potential was lower than -0.2 MPa, the growth of hypocotyls, radicles and cotyledons was inhibited, especially when the osmotic potential of solution was lower than - At 0.6 MPa, the development of cotyledons is also affected. -0.2 MPa is a critical osmotic potential for the growth of Populus euphratica. (3) The radicle and cotyledon growth were more sensitive to NaCl stress, which showed that the seeds could germinate within the concentration range of 0 ~ 0.80 mol·L-1 NaCl, but the growth of radicle and cotyledon at the concentration of 0.05 mol·L-1 There was a significant difference between the control and the control. When the solution concentration was more than 0.10mol·L-1, the cotyledons appeared yellowing phenomenon. In the range of 0.20-0.80mol·L-1, the cotyledon did not develop normally. The rapid and concentrated germination of Populus euphratica seeds is an adaptation to arid and rainy environment. The effects of water and salt stress on the growth of Populus euphratica during germination are the keys to limit the success of Populus euphratica.