白骨壤次生木质部生态解剖学研究

Ecological Wood Anatomy of Avicennia marina

测量了深圳红树林鸟类自然保护区8个不同白骨壤(Avicennia marina)种群采样点土壤的盐分、p H值和养分,应用生物显微技术和电镜技术观察了白骨壤次生木质部的结构形态,不同样地白骨壤次生木质部均具有:(1)纤维状导管;(2)螺旋雕纹和附物;(3)薄壁细胞含淀粉粒;(4)内含韧皮部。依据结构-功能解剖学的研究结果,这些特化结构均有利于提高白骨壤在"生理干旱"生境下栓塞修复能力,增进水分输导的安全性。对白骨壤次生木质部数量特征和土壤理化因子作逐步回归分析,结果表明:随土壤盐度和土壤有机质含量增大,在遭受"生理干旱"越来越严重的情况下,白骨壤能形成更高的复孔率,相邻两导管接触壁平均厚度增加,这可能是适应异质生境的结果。

The soil physicochemical indexes including edaphic pH values, edaphic salinity and soil nutrient indexes were determined in 8 Avicennia marina populations located in national nature reserve of Shenzhen of Guangzhou Province. The morphological characters in secondary xylem of A. marina populations corresponding to soil sampling which represented different habitats were surveyed by means of light microscopy and electronic microscopy. Some common specialized wood structures in A. marina growing in different habitais can be observed which suggest they function as safely conducting water under high negative pressure and are thus adaptive to intertidal habitats. These characteristics include the occurrence of： （ 1 ） some fibriform vessel elements; （2） vessel vestures and helical struc- tures on vessel walls; （3） parenchyma cells contain lots of starch grains; （4） included phloem. Soil organic matter and soil total salt have significant effect on quantitative wood anatomical features by the stepwise regression analysis. With the increase of soil salinity and soil organic matter content which suggest occurrence of more and more serious ＂physiological drought＂, A. marina is characterized by a higher porosity, and double thickness of vessel wall making contact with an adjacent vessel. The trends inferred that variations in the quantitative wood anatomical features of A. marina growing at different sites are adaptive to heterogenous habitats in the intertidal areas.