Study On Development Biology And Systematic Evolution Of Some Species Of Iris

This study from three aspects compares some species of Iris, development morphology from seed embryo to seedling, the seed coat micro morphology and the molecular systematics (nDNA ITS sequence and the cpDNA trnL-F sequence of some species of Iris). Development biology and systematic evolution of some species of Iris were studied. Finally illustrate the species key to analyses main traits comprehensively and make some new progress, as states as follows:1. Development morphologyThe part of embryonic bud growth is better than radiculodium. The prominent performance is that the length above the cotyledonary nodes is longer than below the cotyledonary nodes. The radiculodium is short and obtuse. There is no obvious structure polarization. When the seeds sprout, some individuals have cyclic annular inflated hair zone above early initial roots which close neighbor root tip meristematic zone. These individual characters are similar to most aquatic plants in Monocotyledoneae helodiales and dicotyledon nymphaeales. It may reflect the system germination relations of Iris.Through the experiment and observations of the process of from seeds to the seedlings, I found the stable properties that may use for species iConcaveification are: the number and the position of the vascular bundle from cotyledonary node through the cotyledonary sheath to cotyledon coupling; Whether there is a tongue shape sheath; cotyledon sheath deficiency or not; epicotyl and hypocotyl is obvious or not; the form of bud germination, especially seed structure and the morphology of the first leaf; the swelling morphology of germ sheath when the germ leaf germinates; the position of cotyledon coupling. The swelling morphology of germ sheath is related to the position of cotyledon coupling. If the cotyledon coupling locates in the middle and upside of cotyledonary sheath the cotyledonary sheath will swells along the Embryonic-root. If the cotyledon coupling locates in the underneath of cotyledonary sheath the cotyledonary sheath will swells to be triangular pyramid.2. Seed coat micro morphologyIris seed coat micro morphology characteristics have the stability. That is not relate to distribution areas. But within a species there are differences between concave and convex surface micro morphology. Therefore, we should take middle part well grow fruit, the natural mature seed and chooses the same spot for comparison observation. All of species we studied is reticulate grain (reticulate grain or negative net grain), this is the same patterns with basic grain of Iris pollen. The phylogenetic relationships of Iris plant seed coat are: the reticulation butcher isomorph is more primitive than that with the net butcher different shape; the negative reticulate grain structure is more primitive than that with the net grain structure; the reticulation keel outgrowth not obviously is more primitive than that with the reticulation keel outgrowth obvious or hollowly assumes the honeycomb-shaped decorative design; the mesh shallowly...