【作者】 廉彭彭；

【导师】 周桂玲；

【作者基本信息】 新疆农业大学 ， 植物学， 2008， 硕士

【摘要】 白滨藜(Atriplex cana C. A. Mey.)和疣苞滨藜(Atriplex verrucifera Bieb)是生长在中国西北盐生荒漠的盐生小灌木。本文对这两种盐生植物种子的萌发生态学进行了研究。研究内容包括:(1)温度、苞片和不同的贮藏条件对种子萌发的影响;(2)不同的NaCl浓度对种子萌发和恢复的影响;(3)NaCl浓度对这两种盐生植物幼苗生长和恢复的影响。新成熟的白滨藜和疣苞滨藜种子具有非深度生理休眠,它们分别经过2W和8W的低温层积处理打破休眠。打破休眠的种子萌发的最适温度为昼夜=15/5℃(白滨藜)和25/15℃(疣苞滨藜)。苞片对新采收的白滨藜种子存在机械抑制,层积后苞片的抑制作用减弱;苞片延长新采收的疣苞滨藜种子的萌发时间,但对最终萌发率无显著影响。层积条件下,2W后白滨藜的种子萌发率达到最大,层积8W后活力完全丧失;疣苞滨藜的种子随着层积时间的延长萌发率逐渐上升,8W时达到最大。室温条件下,随着贮藏时间的延长,白滨藜和疣苞滨藜的种子萌发率都逐渐升高,萌发速率逐渐加快。这两种盐生植物种子的萌发对NaCl胁迫响应不同。白滨藜种子在蒸馏水中萌发最好,随着盐溶液浓度的升高萌发率逐渐降低。疣苞滨藜的种子在0.2MNaCl溶液中萌发率最高,之后随着盐浓度的升高萌发率逐渐下降。它们分别在1.2M(白滨藜)和0.8M(疣苞滨藜)NaCl溶液中萌发完全被抑制。将未萌发的种子转入蒸馏水中继续萌发,两种滨藜的种子均能恢复萌发。白滨藜的种子经1.0MNaCl处理后的种子恢复率最高为57.7%,在蒸馏水中的最终萌发率高于各盐度条件下。疣苞滨藜经≥0.6M NaCl处理后,种子的恢复率高于75%,各盐度条件下的最终萌发率都高于对照。疣苞滨藜萌发出的幼苗,其幼芽和幼根的生长受0.2MNaCl溶液促进,根冠比最大,当≥0.4M时伸长逐渐受抑制,且幼根比幼芽受抑制程度大,根冠比下降,≥1.0M时生长完全被抑制。白滨藜萌发出的幼芽和幼根在小于0.2M时不受影响,随着盐度的升高生长逐渐受抑制,根冠比也逐渐下降,当≥0.8MNaCl时,幼苗的生长完全停止。转入蒸馏水中后,两种植物的幼苗都可以继续伸长,伸长能力随预处理盐溶液浓度的升高而降低,幼根的伸长能力比幼芽强。经过≥1.0M和≥0.8MNaCl预处理的疣苞滨藜和白滨藜的幼苗无法继续伸长。实验结果表明:这两种盐生植物在种子萌发和早期幼苗生长阶段对盐渍环境具有适应性。种子和幼苗早期在高盐分胁迫下保持萌发恢复能力和幼根的恢复生长能力是对盐生环境的适应对策。这些适应对策确保这两种盐生植物在新疆的盐渍荒漠中成功定居和繁殖。更多还原

【Abstract】 The small shrubs Atriplex cana C. A. Mey and Atriplex verrucifera Bieb grow in saline deserts in northwest China. The seed germination ecology of the two species was studied in the paper.The research aspects include: (1) Effect of temperature, bracts and store condition on seed germination. (2) Effect of NaCl concentration on seed germination and germination recovery. (3) Effect of NaCl on seedling elongation and elongation recovery after seedings were transferred to distilled water.The freshly matured seeds of A.cana and A.verrucifera have non-deep physiological dormancy. They need 2 and 8 weeks of cold stratification to break the dormancy respectively. After the dormancy had been broken, the optimal condition for seed germination of A.cana is at day/night =15/5℃, A.verrucifera is at day/night = 25/15℃. The bracts inhibited germination of freshly matured seeds of A.cana by mechanical effect,the effect of mechanical effect decreased after cold stratification; the germination time of freshly matured seeds of A. verrucifera was enlonged by bracts, but the final germination didn’t changed significantly. After 2 weeks cold stratification, the germination of A.cana seeds reached the top, but after 8 weeks, seeds lost vitality; the germination of A.verrucifera was increased with the cold stratification, and reached maximum after 8 weeks cold stratification. The seeds germination and the germination speed of A.cana and A.verrucifera increased gradually with the store time under normal condition.The responses of the seeds of the two species to NaCl concentration were different. The germination of A.cana decreased with the increase of salinity and was hightest at distilled water. The germination of A.verrucifera was hightest at 0.2M NaCl and decreased when the concentration of NaCl>0.2M. In the end, the salinities to completely inhibit germination were 1.2 and 0.8MNaCl respectively. When the ungerminated seeds were transferred into distilled water, they can continue to germinate. The recovery percentage of A.cana was highest in 1.0MNaCl, but final germination was highest in non-saline control. While the recovery percentages of A.verrucifera from 3.0MNaCl were all above 75%, and the finale germination percentage was higher than percentage in control. The result indicated that NaCl inhibited germination by osmotic stress.The growth of buds and boots of early seedlings of A. cana were promoted in low concentration(0.2M NaCl), the ratio of root to shoot reached the top.The prolonging of seedlings were inhibited as the concentration≥0.4M, the salt concentrations had more influence on the radicle, and ratio of root to shoot gradually decreased and with the increase of salinity seedling growth was inhibted finally(1.0M NaCl). However NaCl (<0.2M) didn’t effect the growth of scions and radicles of early seedlings of A.verrucifera. The growth was inhibited gradually and ratio of root to shoot decreaded with the increase of the salt. In the end, seedling elongation was completely inhibited by≥0.8MNaCl. Elongation of radicles and scions resumed after seedlings were transferred to distilled water, and their ability to continue elongating decreased with increase in pretreatment concentration of NaCl. The growing ability of radicles was biger than scions. A.verrucifera pretreated by NaCl≥0.8M and that of A.cana pretreated byNaCl concentrations≥1.0M could not grow any more.The results showed that the seed germination and the early growth stages of seedlings of the two species can be adaptable to saline environment. The ability of seeds and seedlings that maintain regerminating and regrowing under high salt stress is one of the special adaptive strategies for them to inhabit the salt desert environment. Those can help them survive and reproduce successfully in the salt desert of Xinjiang.更多还原