NaCl胁迫对滨梅扦插苗生物量和水分积累的影响

以1年生滨梅(Prunus maritima Marshall)扦插苗为实验材料,在盆栽条件下用质量浓度为0.15%、0.29%、0.58%、0.88%、1.17%、1.46%的NaCl溶液进行盐胁迫处理,测定胁迫后根、茎、叶Na+、K+含量以及全叶、一年生茎、二年生茎和根系生物量、含水率、根系活力变化,探讨滨梅的抗盐胁迫机制。结果显示:(1)盐胁迫80d后,随着盐胁迫强度提高,滨梅植株根、茎、叶Na+含量显著提高,而其根、茎K+含量显著降低,根、茎、叶K+/Na+值显著降低;根Na+含量在低于0.58%NaCl胁迫下显著高于茎、叶,而在高于0.58%NaCl胁迫下却表现为叶Na+含量显著高于根、茎。(2)滨梅根、茎、叶生物量均随盐胁迫强度的提高呈先增加后减少的趋势;随着盐胁迫时间的延长,茎、叶生物量在低于0.58%NaCl胁迫下均呈积累趋势,且茎生物量在0.58%NaCl胁迫下显著提高,而根、一年生茎、叶生物量在高于0.58%NaCl胁迫下均显著下降。(3)滨梅茎、叶含水率均随盐胁迫强度的增加呈先增加后减少的趋势,而随着胁迫时间的延长呈逐渐减少趋势;根系活力及根含水率均随盐胁迫强度的提高而增加,但根含水率随着胁迫时间的延长变化不明显。由此可见,滨梅能通过根系稀释并蓄积Na+,保护地上部分正常生长,当进入根系的Na+量超过吸收阈值时,Na+迅速在叶中积累储存,且叶中较高含量的K+对Na+形成了有效的缓冲。

Growth and Water Content of Beach Plum Cutting Seedlings under Salt Stress

Pot culture were conducted to investigate K⁺,Na⁺,biomass and water content changes of different sections of beach plum(Prunus maritima Marshall) cutting seedlings,which were irrigated with NaCl solutions of 0.15%,0.29%,0.58%,0.88%,1.17% and 1.46% mass concentration.The result showed that:(1)80 days after the irrigation,with the stress increasing the Na⁺ content in roots,stems and leaves increased,while K⁺ content in roots and stems and K⁺/Na⁺ decreased.The K⁺ content in leaves was much higher than that in other organs,which remained steady during the experiment.(2)With the increasing salt stress level/time,the leaf,shoot and root dry weight showed their descending following their ascending,and an apparent consumption of dry weight was derived from the 0.88%-1.46% NaCl irrigation.(3)Water content in shoots and leaves was significantly reduced due to the continuous salt stress,but root activity and water content evaluated in an opposite direction,that shows the beach plum builds up a salt-dilution and Na⁺ storage method by accelerating its root succulence.In addition,more Na⁺ accumulates in leaves under a harsher salty condition.