Abstract

Physiological and biochemical traits for Salsola drummondii, a habitat-indifferent xerohalophyte, were compared in plants collected from two habitats differing in soil salinity (saline habitat, SH and non-saline habitat, NSH) to understand possible mechanisms of salt tolerance. Samples from different plant organs and soils were collected from the two habitats to assess average leaf fresh and dry weights, leaf succulence (SWC), chlorophyll pigments (Chl a, b, carotenoids), lipid peroxidation (MDA), H₂O₂ content, antioxidant enzymes activity (catalase, CAT; ascorbate peroxidase, APX and guaiacol peroxidase, GPX), stable carbon isotope composition (δ¹³C) and elemental composition. No significant reduction in the leaf biomass and leaf succulence was observed in plants from the two habitat types. We found an increase in activities of antioxidant enzymes (CAT, APX) that would enhance the stress tolerance in plants from the SH. Na⁺ accumulation in the leaves was significantly greater in plants from SH than in those from NSH. The hyper-accumulation of Na⁺ didn’t impact the concentrations of other essential nutrients. Hydrogen peroxide accumulation was significantly greater in roots than in shoots of plants from SH than in NSH, but there was no difference in shoots. δ¹³C was less negative in SH as compared to NSH. We concluded that S. drummondii is a sodium accumulator and this does not disturb much its normal plant growth. For osmotic adjustment, plants of SH rely more on Na⁺, but those of NSH rely on proline as osmoregulator. Therefore, S. drummondii may be useful for restoring degraded sodium-affected lands.

摘要

比较了从土壤盐分不同的两个栖息地（盐碱地，SH 和非盐碱地，NSH）收集的植物中猪毛菜（一种与栖息地无关的旱生植物）的生理和生化特征，以了解耐盐性的可能机制。从两个栖息地收集来自不同植物器官和土壤的样本，以评估平均叶片鲜重和干重、叶片肉质（SWC）、叶绿素色素（Chl a、b、类胡萝卜素）、脂质过氧化（MDA）、H ₂ O ₂含量，抗氧化酶活性（过氧化氢酶，CAT；抗坏血酸过氧化物酶，APX 和愈创木酚过氧化物酶，GPX），稳定的碳同位素组成（δ ¹³C) 和元素组成。在来自两种栖息地类型的植物中没有观察到叶片生物量和叶片肉质的显着减少。我们发现抗氧化酶（CAT、APX）的活性增加，这将增强来自 SH 的植物的胁迫耐受性。来自 SH 的植物叶片中Na ⁺积累显着高于来自 NSH 的植物。^{Na +}的过度积累不会影响其他必需营养素的浓度。过氧化氢在根中的积累显着大于在 SH 中的植物的芽中，而不是在 NSH 中，但在芽中没​​有差异。与 NSH 相比，SH 中的δ ^{13 C 负值较小。}我们得出结论，S.drummondii是一种钠蓄积剂，这不会对其正常的植物生长造成太大影响。在渗透调节方面，SH 的植物更多地依赖 Na ⁺，而 NSH 的植物则依赖脯氨酸作为渗透调节剂。因此，S.drummondii可能有助于恢复受钠影响的退化土地。