Evolutionary Morphological and Molecular Systematical Study of Rheophytes

1.通过对热带和近缘旱地植物叶片的解剖学比较研究，发现热带和近缘旱地植物的叶肉细胞、表皮细胞和细胞间隙较小，角质层和上表皮蜡质较厚。2.在叶片发育过程中，流生薇菜和旱地薇菜在细胞增殖阶段相似，但在细胞膨大阶段存在明显差异。为了探讨流生植物配子体的适应策略，对两种植物配子体的发育过程进行了比较研究。矛叶野生稻配子体发育到生殖成熟期的速度快，产生孢子体的频率高。4.在田间条件下，将处于幼孢子体发育期（1年生）的旱地粳稻移出流生区，并在流生区的配子体发育过程中，将流生配子体与旱生配子体分离。在叶片形态和解剖结构上，兰芝和粳稻的差异出现在第5或第6叶龄，与田间种群的变化相一致。5.流生三叉蕨的一个阔叶变种与流生植物的遗传分化较小，与旱地植物的解剖结构有显著的相似性。

1.A Comparative leaf anatomical study of tropical rheophytes and closely related dryland species demonstrated that the rheophytes have smaller mesophyll cells, epidermal cells, and intercellular space as well as the thicker cuticular layr and epicuticular waxs, than the dryland species. These anatomical features are strongly correlated to the narrow leaves of rheophytes.2.During the leaf development of the rheophytic Osmunda lancea and the dryland O.japonica, whereas they are similar at the cell increment stage, there is a distinct difference in the cell enlargement stage. The cell increment stage in O.lancea is shorter than in O.japonica, suggesting heterochrony(progenensis).3.In order to examine the adaptive strategy of rheophytic gametophytes, a comparative developmental study of gametophytes of O.lancea and O.japonica was made. The gametophytes of O.lancea grow faster to reach reproductive maturity and produce sporophytes at higher frequency than those of O.japonica. The rheophytic gametophyte takes a strategy different from that of the dryland gametophyte.4.In the field the dryland O.japonica is removed from a rheophytic zone during a young (1-year old) developmental stage of sporophyte. Morphological and anatomical differences of leaves between O.lancea and O.japonica appear at the 5th or 6th youngest leaf stage, corresponding with the populational change in the field.5.A broad-leaved variant of the rheophytic Tectaria lobbii shows quite a small genetic divergence from the rheophyte and a remarkable anatomical similarity to dryland species.