棉花li突变体生长素极性运输的减弱

陆地棉(Gossypium hirsutum L.)li突变体叶片卷曲，植株扭曲，种子表皮毛明显偏短。通过扫描电子显微镜(SEM)观察发现，li突变体的纤维发育在起始期与野生型植株并无明显差异，但在伸长期开始后，如开花后3d(3 day post anthesis，DPA)，纤维伸长受阻；li突变体茎的形成层和韧皮部分化发育不完全，生长素由顶端向基部的极性运输能力下降，仅为野生型植株的大约三分之一。推测棉花li突变体包括纤维发育不良在内的多效性异常表型，与其生长素极性运输能力的下降有关。

Impaired Polar Auxin Transport in Cotton li Mutant

Cotton (Gossypium hirsutum L.) li mutant has greatly shortened fibers (seed-hairs), curling leaves and distorted organ appearance (Fig.1; Fig.2A,B).Observation with SEM did not reveal clear difference in fiber initiation and early growth between the wild-type and li mutant ovules (Fig.2C). However, during elongation stage (e.g., 3 days post anthesis, DPA), fibers of li mutant showed little growth, and were significantly shorter than those of wild type. Stem transection showed an incomplete differentiation and development of cambium and phloem in li mutant (Fig.4). An assay of polar auxin transport showed that the basipetal transport activity was much lower in the stem of li mutant than in the stem of wild type plants (Fig.3). These results suggest that pleiotropic changes in li mutant, including early stop of fiber elongation, are likely related to impaired polar auxin transport.