不同盐分类型胁迫对豌豆幼苗离子吸收、累积及运输的影响

摘要

为了探究不同类型盐分（NaCl、混合 Na 盐和混合 Cl 盐）胁迫下3个品种（‘银豌1号’、‘S5001-1’和‘737’）的豌豆幼苗对离子吸收与运输的生理机制，采用水培方法对3个品种的豌豆幼苗的盐分离子吸收、分布、累积特性进行了研究。结果表明，1）3个品种的豌豆幼苗在 NaCl 和混合 Na 盐处理下，地上部和根系 Na＋含量较对照均显著增加，而 K＋、Ca2＋含量则显著降低；混合 Cl 盐处理下，豌豆幼苗地上部和根系 Na＋含量较对照均无显著差异，而Cl－、K＋、Ca2＋和 Mg2＋含量均显著高于 NaCl 处理和混合 Na 盐处理。2）3个品种的豌豆幼苗在正常生长条件下均优先吸收并富集 K＋，其次是 Ca2＋；在 NaCl 和混合 Cl 盐处理下优先吸收并富集 K＋，其次是 Na＋和 Cl－；混合 Na盐处理下则优先吸收并富集 Na＋和 K＋，其次是 Ca2＋，但不同处理下离子的分布和累积状况在不同品种的豌豆幼苗间有所不同。3）NaCl 和混合 Na 盐处理下，3个品种的豌豆幼苗的离子选择性吸收系数 SAK，Na 、SACa，Na 和SA Mg，Na 显著升高，而在混合 Cl 盐处理下显著降低。同一处理下，3个品种的豌豆幼苗间的离子选择性运输系数也表现不同，NaCl 和混合 Na 盐处理下，‘S5001-1’的 ST K，Na 和 ST Ca，Na 较对照显著升高，而‘银豌1号’的 ST K，Na 和ST Ca，Na 在混合 Na 盐和混合 Cl 盐处理下较对照显著降低，3个品种的豌豆幼苗间的 ST K，Na 在混合 Cl 盐处理下无显著差异。以上结果说明，NaCl 和混合 Na 盐处理下，豌豆幼苗地上部对 Ca2＋、K＋和 Mg2＋的累积量明显下降，同时为了应对盐分胁迫，根系对 Ca2＋、K＋和 Mg2＋的吸收及运输能力则显著增强；在混合 Cl 盐处理下，豌豆幼苗地上部对 Ca2＋、K＋和 Mg2＋的吸收及累积量较其他两种盐分处理明显增加，但根系对于 Ca2＋、K＋和 Mg2＋的吸收及运输能力则显著低于其他两种盐分处理，而且品种间差异显著。本结果对于阐明不同盐分类型胁迫下植物对离子吸收与运输的生理机制提供一定的理论依据。%In order to investigate the physiological mechanisms of ion absorption,accumulation and transporta-tion in pea seedlings under various types of salt stress (NaCl,mixed sodium salts and mixed chlorine salts,the control treatment was Hoagland nutrient solution),the characteristics of absorption and accumulation of ions in three varieties of pea (‘Yinwan NO.1 ’,‘S5001-1 ’and ‘737’)seedlings were studied using a hydroponic method.Key findings were:1)Under NaCl and mixed sodium salt stress,Na+ contents in shoots and roots were significantly higher than control,whereas contents of K+ and Ca2 + were significantly lower.Under mixed chlorine salt stress,Na+ contents in shoots and roots did not differ significantly from those of control plants. However,contents of Cl- ,K+ ,Ca2 + and Mg2 + were significantly higher than for the other two salt treat-ments.2)Under the control treatment,K+ was absorbed and accumulated prior to other ions in three varieties of pea,followed by Ca2 + .Under NaCl and mixed chlorine salt stress,K+ was absorbed and accumulated prior to other ions,followed by Na+ and Cl- .Under mixed sodium salt stress,Na+ and K+ was absorbed and accu-mulated prior to other ions,followed by Ca2 + ,while the characteristics of transportation and accumulation of salt ions among three varieties of pea were different under various types of salt stress.3 )Under NaCl and mixed sodium salt stress,the selective absorption coefficients SAK,Na 、SA Ca,Na and SA Mg,Na in the three varieties of pea were significantly higher than in control plants,while significantly lower than under mixed chlorine salt. The ST K,Na and ST Ca,Na in ‘S5001-1 ’seedlings were significantly higher under NaCl and mixed sodium salt stress than in control plants,whereas the ST K,Na and ST Ca,Na in ‘Yinwan NO.1’under mixed sodium salt and mixed chlorine salt treatments were significantly lower than for controls.The ST K,Na of the three varieties of pea were similar under mixed chlorine salt stress.The study showed that the accumulation of Ca2 + ,K+ and Mg2 + in shoots under NaCl and mixed sodium salt stress was lower than control,whereas the ability of roots of pea seedlings to absorb and transport Ca2 + ,K+ and Mg2 + was weakened in response to salt stress.Under mixed chlorine salt stress,the absorption and accumulation of Ca2 + ,K+ and Mg2 + in shoots was higher than under the other two salt treatments (NaCl and mixed sodium salts),whereas in roots they were significantly lower than under other two salt treatments.