以2年生牡丹花石榴为供试材料,研究NaCl胁迫对石榴枝、根韧皮部和木质部的Na^+、K^+含量及K^+/Na^+值的影响。结果表明:随着土壤中NaCl含量的增加,石榴植株枝、根的Na^+含量整体呈增加趋势;K^+含量呈先增加后降低趋势,NaCl含量为0.4%时,K^+含量最高。相同NaCl处理下石榴枝的Na^+、K^+含量高于根部,而同一枝、根部位韧皮部的Na^+、K^+含量高于木质部(NaCl 0.5%、0.6%处理的K^+含量除外)。低度盐胁迫(NaCl 0~0.4%)下K^+/Na^+值较大;而高度盐胁迫(NaCl 0.5%、0.6%)下K^+/Na^+值降低,且小于1。土壤中NaCl含量为0~0.4%时,牡丹花石榴可正常生长,过高则出现叶片黄化、落叶、生长不良的现象。
Two years old Mudanhua pomegranate seedlings were used as materials.The change of Na^+ and K^+ contents and K^+/Na^+ ratios in phloem and xylem of branch and root of pomegranate plants under salt stress.The results showed the contents of Na^+ increased with the increase of NaCl concentration in soil;the contents of K^+ first increased and then decreased,when the NaCl concentration reached 0.4%,the contents of K^+ reached the peak value.The contents of Na^+and K^+were higher in branches than that in roots,the contents of Na^+ and K^+ were higher in phloem than that in xylem except the K^+ content under 0.5% and 0.6% NaCl stress.The K^+/Na^+ ratios were higher under hyposaline conditions(NaCl concentration of 0-0.4%)than that under hypersaline conditions(NaCl concentration of 0.5%-0.6%),and the K^+/Na^+ ratios were less than one under hypersaline conditions(NaCl concentration of 0.5%-0.6%).Mudanhua pomegranate growed normally when the NaCl concentration was below 0.4% in soil,and high NaCl contents could cause leaf blade yellowing and falling,and negative growth.