盐胁迫对芦笋幼苗生长和体内Na^+,K^+,Ca^(2+)分布的影响

Effects of Salt Stress on the Growth of Asparagus officinalis L.Seedlings and on Na^+,K^+ and Ca^(2+) Distribution in Them

以芦笋品种NJ978为试材,研究了NaCl胁迫对芦笋幼苗生长及体内Na+,K+,Ca2+吸收和分布的影响,结果表明:盐分对芦笋幼苗生长的抑制作用随NaCl浓度的增加而加剧,低盐胁迫下(NaCl≤50mmol/L),芦笋生长与对照没有显著差异,高盐胁迫(200~300mmol/L NaCl)显著抑制了幼苗生长.随NaCl浓度的增加,芦笋体内Na+含量增加,K+,Ca2+含量降低.芦笋根系对Na+有一定的截留能力,低盐环境下(NaCl≤100mmol/L),根部Na+迅速增加,而地上部Na+增加缓慢,从而抑制了Na+向地上部运输,并维持了地上部相对稳定的K+,Ca2+平衡;外界NaCl浓度高于根系Na+截留阈值后(100mmol/L),大量的Na+运输至地上部并限制了K+,Ca2+的吸收,表现为K+/Na+和Ca2+/Na+迅速下降.芦笋根系对K+,Ca2+,Na+选择吸收性(ASK,Na,ASCa,Na)随盐胁迫增加而变高;根部向地上部运输K+,Ca2+能力(TSK,Na,TSCa,Na)在0~100mmol/L NaCl水平下逐渐升高,之后迅速下降.以上结果表明:根部对Na+的截留和Na+,K+,Ca2+在器官水平上的再分布是芦笋适应盐胁迫的重要机制之一.

A sparagus officinalis L. cultivar NJ978 was used to study the growing rate, salt ion content and mineral ion uptake and distribution in the plant under salt stress. The results showed that there was a neg-ative relationship between seedling grow th and salt concentration. Seedlings grow th was not significantly inhibited under low salt stress （NaCl ≤ 50 mmol/L）, but high concentrations of NaCl （200 - 300 mmol/L） had a detrimental effect on the growth of A. officinalis.Na ＋ content increased and K ＋ and Ca2 ＋ content decreased in A. officinalisroots, stems and leaves with increasing NaCl concentration. Under low salt stress, the seedlings of A. officinalis could in hibit Na ＋ from transporting to the aerial part of the plant by withholding Na＋ in the root, thus maintaining a relative balance of ions in the aerial part. Under high salt stress （NaCl 〉 100 mmol/L）, the aerial part of seedlings accumulated superabundance of Na ＋, the up-take of K ＋ and Ca2 ＋ was limited, the seedlings were damaged heavily, as was manifested as a rapid de-crease in K ＋ /Na ＋ and Ca2 ＋ /Na ＋ in the plant. The selective absorption of K ＋, Ca2 ＋ and Na ＋ （ASK, Na and ASCa, Na） was significantly increased with increasing salinity, and the selective transportation of K ＋and Ca2 ＋ （TSK, Na and TSCa, Na） increased at first and then decreased with increasing salinity. The im-pediment by the root of the upward transport of Na＋ and the redistribution of ions in the root, the stem and the leaves could be an important mechanism for salt tolerance of A. officinalis.