干旱胁迫下不同苎麻品种的形态解剖特征研究

抗旱性强的苎麻品种,在正常水分条件下叶面茸毛多、叶着生角度小、比叶重大,而在干旱胁迫下叶片衰老慢,根冠比大、根活跃吸收面积大、萝卜根数量多且直径大,纤维细胞直径和胞壁厚度降低幅度小。抗旱性强的苎麻品种正常水分及干旱条件下叶片气孔密度以及茎导管和根系维管束均较大。

Study on Morphological and anatomic characteristics of ramie varieties under drought conditions

Six ramie varieties were investigated for their morphological and anatomical characteristics under drought stress via soil and sand culture in drought-pools,and aqueous culture in presence of polyethylene glycol.To compare with the average varieties,the varieties with strong resistance to drought had denser fine-hairs on the down-side of leaves,erect leaves (small angle between the petiole and stem),and greater specific leaf weight (g/dm -2 )under normal soil water status. Under drought stress,these vareties had a slower leaf senescence rate,greater root-canopy ratio,larger active absorption surface of roots,more and bigger carrot-shaped roots (a specialized storage root of water and nutrients),and less decrease in fiber size and the thickness of biber-cell wall than the average varieties.Moreover,these varieties had higher density of stomata in leaves,larger stem vessels and root vascular bundles under both conditions of normal soil water status and drought stress.