| Salix L. is the largest genus in Salicaceae, which has more than520species inthe world and275in China. They are mainly distributed in the north temperate zoneand a few of them distributed in subtropical regions. Some species of Salix are thebest choice for protective candidat along banks of rivers, dams and gardens. CurrentlyS. matasudana, S.babylonica and their relevant varietas are the most planted and a lotof Salix species are not naturalized. By going through all related reference materialsand investigating almost the whole country to check the current distribution of Salixspieces, collecting specimens and molecular materials about100kinds of more than1000types and taking some fresh samples back to school to cultivate, we use all thesematerials and informations to do scanning of electronic microscope(SEM) andmolecular systems researches and got the results as follows:1. Survey on resources of genus SalixThe live Salix genus of faced been threatened, some of the species are evenendangered. Almost all willows can be easily grew by cutting and growing fast whichmake their introductions have highly successful rate, meanwhile, many species ofSalix genus have peculiar leaves patterns and good looking tree forms, making themthe good choice for forestation and garden. We should greatly develop Salix potentialapplications.2. Obversition under scanning electron microscopeUsing electron microscope to firsty obverse70spieces leaves lower epidermis ofSalix at the micro state, and we found out9waxy patterns in which non entireplatelets, membraneous platelets, rosettes of platelets and cylindrical corpus fibrosumwhich have not reported before.According to the study of S. tetrasperma and S. araeostachya at their differentgrowth stages with the leaves’ wax’s changes, as with the growth of the leaves, the wax will grow and change. When the leaves are ripe the wax will have stable featuresand not change by the living environment, but the wax’s pattern is related withenvironment, which of the genus Salix growing in the cold zones have variouspatterns of wax and the wax layer is more thicker, this result comes from the genusSalix live against with climate in long term, it is also the change of the genes in plant.By comparing the waxiness patterns of Wilsonianae and Vimen in which somespecies are similar to each other, we found that waxiness helps to distinguish thoseeasily confused Salix species very well.Through studying of18species of Salix genus with foliaceous back with fluff,sorting their length, thickness and waviness, also comparing to their status inmacrography, it shows that the microstructure of Salix studied by scanning electronmicroscope is not as obvious as its morphology (thin hair, sericea hair and fine hairetc), its microstructure is mainly showing the differences of the hair’s thickness,length and waviness patterns (sorted by straight, micro bending and deep bending)3. Researches of molecular systemsAfter analysing the32species of52copies of subgenus Salix which is difficult tobe classified, we find that molecular systematics prove that Chosenia should beincorporated into Salix and merging with Toisusu as one clades. S. songarica inAmygdalinae has few relationships with the other two species in this sect, supposed tobe a individual piece. S. tetrasperma and S. araeostachya are very alike no matter inmicrostructure and morphology which can be treated as one spiece. Regarding to theWillsonii, it can be sorted into two clades, one clade are S. wilsonii, S. chaenomeloide,S. dunii, S. nankingensis, S. cavaleriei, and the other group are S. warburgi, S.kusanoi, S. mesnyi and S. rosthornii. |
