在温室培养条件下，用叶片喷雾的方式对盐生植物榄仁（Terminalia catappa）的幼苗进行NaCl胁迫处理，研究了盐雾胁迫对其生长、5种矿质元素（Ca2+、Mg2+、Na+、K+、Cl-）和灰分在幼苗不同叶龄叶片和叶片各部分分布的影响，以探讨盐雾胁迫下的盐害机理，以此指导实际工作中盐害诊断与预防措施，为筛选耐盐树种建设沿海防护林提供依据。结果表明：盐雾胁迫下榄仁幼苗的叶、茎、根生长比对照组缓慢，K+在各叶片分区的分布差别较小，Ca2+、Mg2+、灰分在叶片中心区分布较多，Na+和Cl-均向叶缘集中，且Na+和Cl-质量分数显著增加（P<0.05），可见盐雾胁迫下榄仁幼苗叶片盐分较易集中在叶尖、叶缘，这与叶片病斑多分布于叶尖、叶缘的症状相符。盐雾胁迫下榄仁幼苗叶片的灰分质量分数在叶片中心区分布最多，并呈现老叶>成叶>新叶，而且随胁迫时间增加呈升高趋势，叶片不同部位和不同叶龄的灰分质量分数都显著高于对照组（P<0.05），故盐雾胁迫促进植物体灰分积累。盐雾胁迫下榄仁幼苗的 K+、Na+、Cl-在新叶分布最多，Ca2+在老叶分布最多，Mg2-在成熟叶分布最多，可见新叶对盐雾胁迫最敏感。不论是在叶片不同部分、不同叶龄的分布，还是在盐雾胁迫下5种矿质元素质量分数的变化上，榄仁幼苗体内的Na+-Cl-存在极显著强正相关（P<0.01）。%In order to understanding the mechanism of salt damage on halophyte Terminalia catappa seedlings, the seedlings were treated with NaCl in greenhouse by leaf spray, then their growth rate, and the allocation of mineral elements and ash in the different age and parts of the leaf were measured, which may guide the salt damage diagnosis and prevention measures in practical work, provide a basis for screening the salt tolerance species and constructing the coastal shelter forest. The results showed that the growth rate of leaf, stem and root of Terminalia catappa seedling treated by salt spray was slower than that of control group. There was no significant difference on the distribution of K+in the different parts of the leaf. Ca2+and Mg2+, and Na+and Cl-mostly distributed in the center part of leaves and at the edge of leaf, respectively. Moreover, the mass fraction of Na+and Cl-was significantly increased (P<0.05). Therefore, the salinity mainly distributed on the leaf tip and leaf edge after salt spray, which coincided with the symptom of lesions distributed mostly on the leaf tip and leaf edge of Terminalia catappa seedling. The mass fraction of ash of Terminalia catappa seedling mainly distributed in the center part of leaves after salt spray and increased with salt spray time. The order of mass fraction of ash was old leaves>mature leaves>new leaves. Furthermore, the mass fraction of ash in the different age and parts of the leaf treated by salt spray was significantly higher than that of control group (P<0.05). So the accumulation of ash in the plant increased with the treatment of salt spray. K+, Na+and Cl-, Ca2+, and Mg2+on Terminalia catappa seedling mainly distributed on the new leaves, the old leaves, and the mature leaves, separately showing that the new leaves were the most sensitive to salt. A significantly positive correlation between Na+ and Cl- was found in the plant with the treatment of salt spray in spite of the distribution of mineral elements in the different age and parts of the leaf, and the alteration of mass fraction of mineral elements (P<0.01).
展开▼
