牛叠肚幼苗对盐胁迫的离子响应

Response of Ions in Rubus crataegifolius Seedlings to Salt Stress

以牛叠肚(Rubus crataegifolius)1 a生组培苗为试材,采用盆栽土培法研究不同浓度NaCl(0、30 mmol·L-1、60 mmol·L-1、90 mmol·L-1、120 mmol·L-1)处理对牛叠肚幼苗含水量及其体内Na+、K+、Ca2+吸收、运输与分配的影响。结果表明:NaCl胁迫浓度≤90 mmol·L-1范围内,牛叠肚幼苗含水量均高于对照,且维持在较稳定的水平,这将有利于减轻盐胁迫造成的生理干旱。NaCl胁迫处理下,牛叠肚幼苗根、茎、叶中Na+含量较对照显著增加,且茎中Na+含量显著高于根和叶;叶片中K+含量较对照显著降低,而Ca2+含量则较对照显著增加。随着胁迫浓度的升高,各器官中K+/Na+和Ca2+/Na+比值总体呈下降趋势,但叶片中K+/Na+、Ca2+/Na+始终保持相对较高比值,这对于维持叶片正常的生理功能具有重要意义。NaCl胁迫下,牛叠肚根向茎选择性运输Na+能力提高,而茎向叶选择性运输K+和Ca2+能力增强,茎中截留大量Na+,这有利于减缓盐胁迫对叶片和根系的伤害。该研究为深入了解牛叠肚盐碱适应机制提供了理论依据,同时也为牛叠肚的开发利用提供了一条新途径。

The effects of NaCl with different concentrations（ 0,30,60,90 and 120 mmol · L^-1） on the water content and absorption,transport and distribution of Na^＋,K^＋,Ca^2＋ in the 1-year-aged potted seedlings of Rubus crataegifolius were investigated. The results revealed that the water contents in the 1-year-aged potted seedlings of R. crataegifolius under the stress of NaCl with concentration ≤90 mmol · L^-1were higher than those of contrast seedlings,and they were maintained a stable level under the stress of NaCl with concentrations of 30,60 and 90mmol·L^-1respectively. Therefore,the capability of the seedlings to absorb water was enhance,which is beneficial to reduce the physiological drought caused by salt stress. Under the NaCl stress,the Na^＋concentrations in the roots,stems and leaves of the R. crataegifolius seedlings were significantly increased compared with those of the contrast seedlings,and the Na^＋concentration in the stem was significantly higher than that in roots and leaves. Moreover,the K^＋concentration in the leaves was significantly decreased but the Ca^2＋ concentration was significantly increased. The ratios of K^＋/ Na^＋and Ca^2＋ / Na^＋in most organs were generally decreased with the increase of NaCl concentration,but they were relatively high in leaves,which is of important significance for maintaining the normal physiological functions of leaves. Under the NaCl stress,the selective transport capability of Na^＋from roots to stems was enhanced,and the selective transport capabilities of K^＋and Ca^2＋ from stems to leaves were also increased,and large amount of Na^＋was retained in stems,which is advantageous for reducing the damage of salt stress to leaves and roots This study results could provide the theoretical basis for deeply understanding the adaptive mechanism of R. crataegifolius in saline or alkaline environment,and also a new path of utilizing R. crataegifolius.