摘要
利用扫描电镜和 X射线电子探针研究了星星草 (Puccinellia tenuiflora)的叶表皮及其与生境高盐的关系。结果表明 ,叶表皮由表皮细胞和气孔器组成 ,下表皮气孔器多于上表皮 ,且常下陷 ,表皮具表皮毛。表皮细胞外存在丰富的蜡质纹饰和蜡质颗粒 ,这些蜡质包含盐离子 ,具有泌盐的功能。这些特征表明星星草受外界生态因素的影响 。
As an adaptive consequence, plants growing in saline habitats have developed various salt tolerant mechanisms such as ion selectivity through the membrane system and intracellular ion compartmentation, anatomical modifications such as salt gland on their leaves and special transfer cells for ion transport. Puccinellia. tenuiflora is prevalent in the saline swamps of northern China where soil is essentially composed of sodium carbonate, sodium sulphate or sodium chloride. P. tenuiflora grows well in these areas because of its high salt tolerance. Based on reported work, it was thought that the salt tolerant mechanism of P. tenuiflora could be attributed to their high ion selectivity. From data obtained through leaf-washing experiments, it appeared that the salt tolerance of P. tenuiflora was due to salt excretion through the leaves. However, the salt gland was not observed. This study investigated epicuticular wax from the leaf epidermis of P. tenuiflora as a mode of salt excretion using environmental scanning electron microscopy and X-ray electron probe microanalysis through different preparation methods for structure and elemental analysis. The results showed that the epidermis consisted of epidermis cells and stoma complexes. On the lower surface of leaves, epidermal hairs were observed along with a mass of sunken stomata grouped in parallel rows between the veins. In addition, wax ornamentation and wax grains were present on the surface of the leaves. These structures are characteristic for plants resisting the saline-alkaline and the drought environment. Wax ornamentation and wax grains contained significant amounts of salt ions in response to salt stress. This indicated that epicuticular wax possessed salt excretion capability. Therefore, it is reasonable to assume that the epicuticular waxes of P. tenuiflora may undergo structural and physiological changes to excrete salt ions and adapt to halomorphic conditions.
出处
《生态学报》
CAS
CSCD
北大核心
2004年第11期2451-2456,共6页
Acta Ecologica Sinica
基金
国家自然科学基金资助项目 ( 3 0 2 70 2 3 4)
扬州大学高层次人才科研启动基金资助项目~~
关键词
星星草
叶表皮
蜡质层
泌盐
生态适应
Puccinellia tenuiflora
leaf epidermis
epicuticular wax
salt excretion
ecological adaptation
