橡胶树人工多倍体的形态性状与产胶特征

Studies on Morphological Characters of Somatic Polyploids of Hevea brasiliensis

以经秋水仙素诱导成功的海垦2、PR107和RRIM6003个品系多倍体(处理)为材料,以它们的亲本二倍体为对照,研究16a树龄橡胶树人工多倍体无性系的形态特征和干胶含量。结果表明:3个橡胶品系具有多倍体的形态特征,又表现出嵌合性。它们的树围、生势不及相应的二倍体,干胶含量也不优于二倍体。大多数多倍体植株的树干表面呈现不同程度的隆凸或凹陷。叶片的叶形指数、一级侧脉数、主脉导管列数、栅栏组织厚度、海绵组织厚度和叶片厚度6个主要性状在多倍体与二倍体之间均存在显著或极显著差异,体现了多倍体与二倍体之间的差异性;但在多倍体的植株间或部位间以及二倍体的植株间或部位间,表现出来的差异性错综复杂,无一定的规律性。多倍体树皮结构与二倍体的差异也很明显,如多倍体射线较二倍体的少,射线细胞较宽,树皮弦切面上的“网眼”(多列射线排列成的梭状结构)较宽、形状不规则、排列较混乱等。

Morphological characters and dry rubber contents of somatic polyploidy clones which was induced with colchicine16years ago from three Hevea brasiliensis clones Haiken-2,PR107and RRIM600were studied with their diploidy parents as control.The results showed that these clones were polyploids with the morphological characters of both polyploidy and mosaics.Their girth,growth vigor and dry rubber contents were inferior to those of their parent diploids.Trunks of most polyploid trees showed protrusion and depression to some extents.Significant or highly significant difference was found between the polyploids and diploids in six major leaf morphological characters,eg.leaf-shape index,pairs of primary lateral veins,the number of vessel columns in main veins,and thickness of palisade and spongy tissue and leaf blade.This suggests difference between the polyploids and diploids.However,the differences among trees or parts of the same tree within polyploids or diploids were complicated and random.The bark structure was obviously different between the polyploids and diploids.The bark of the polyploids displayed fewer multiseriate rows but wider ray cells,and the″mesh eyes″,multiseriate contour in a tangential section,were wider,irregular in shape,and disorderly arranged,as compared to the diploids.