盐碱胁迫对白刺幼苗生理特性的影响

Effects on Physiological Characteristic of Nitraria tangutorum Under Saline-alkali Stress at Seeding Stage

以一年生实生白刺(Nitraria tangutorum)幼苗为实验材料,设置四种组分(中性盐Na Cl、Na2SO4(1:1)、碱性盐Na HCO3、Na2CO3(1:1)、混合盐碱Na Cl、Na2SO4、Na HCO3、Na2CO3(1:1:1:1)和单盐Na Cl和四个浓度梯度(100、200、300、400mmol/L)的盐碱组成来模拟大田的盐碱土,对白刺(N.tangutorum)的耐盐性进行盆栽试验研究。试验结果表明:白刺(N.tangutorum)幼苗可以耐受不超过300mmol/L的四种组分盐碱胁迫,随着处理浓度的升高,白刺(N.tangutorum)幼苗的细胞膜透性逐渐增加,膜质过氧化程度加剧,SOD及POD保护酶活性逐渐降低。白刺根、茎、叶中的Na+含量和Na+/K+随着处理浓度的增大呈上升的趋势,K+含量则逐渐下降,白刺体内根、茎、叶3个部位中Na+、K+含量和Na+/K+大小顺序依次为叶>茎>根。另外,不同组分盐碱胁迫下,白刺(N.tangutorum)幼苗的生长状态存在差异,高浓度碱性盐胁迫下最早出现植株萎蔫症状,且相对生长量较低,表明白刺(N.tangutorum)对不同组分的盐碱胁迫具有不同的耐盐性,碱对其危害更大。

One year seedlings of Nitraria tangutorum sown in plastic pots were used as experimental materials, and four kinds of saline-alkaline treatment were set up for salinity tolerance experiments. This experiments used neutral salt(Na Cl:Na2SO4,1:1), alkali salt(Na HCO3:Na2CO3,1:1), salt-alkali mixed(Na Cl: Na2SO4:Na HCO3:Na2CO3,1:1:1:1) and simple salt Na Cl to stimulate the field of saline and alkali soil composition. We tested seedlings of N. tangutorum to the four kinds of mixed salt solution stress with 100, 200, 300 and 400mmol/L, respectively. The results showed that N. tangutorum seedlings can tolerate no more than 300mmol/L of the four mixed salt solution stress. With the increased concentration, cell membrane permeability and lipid peroxidation of N. tangutorum seedlings were increased gradually. Enzyme activities of peroxidase(POD) and superoxide dismutase(SOD) both were decreased with the increased concentration. Further comparison showed that the growth conditions of N. tangutorum seedlings were influenced significantly different under the four mixed salt-alkali solution stress. Especially the influence of high alkali salt treatment was one of the most serious among them, and its wilting symptom and low relative growth of N. tangutorum seedlings were first appeared. We concluded that there are different salt tolerance mechanisms in response to the four kinds of mixed salt-alkali stress, the alkali salt were the greatest danger for N. tangutorum seedlings.