吊兰根负向光性表现与机理研究

以吊兰气生根经水培后长出的不定根和侧根为试材，研究其在单侧光照射下的负向光性表现及其机理与调控。结果表明：（1）所有吊兰不定根和侧根均具有负向光生长的特性，最大弯曲角度可达88.5°。（2）负向光性发生受蓝紫光诱导而红光无效，接受光刺激的部位为根冠，在一定光强范围内，根弯曲角度随着光强的增加而增大。（3）外源CaCl2促进吊兰根负向光性弯曲，而外源LaCl3（钙通道阻断剂）抑制负向光性形成，CaCl2可缓解LaCl3的抑制效应。（4）单侧光诱导吊兰根向光侧IAA向背光侧横向运输，而外源Ca2+促进这种单侧光诱导的生长素横向运输，外源LaCl3则抑制这种效应。推测吊兰根负向光性的形成过程大致为根冠细胞受到单侧光刺激后导致IAA从向光侧向背光侧运输，抑制背光侧细胞的生长，从而使两侧细胞生长不均等，而Ca2+作为第二信使介导了这一过程的发生。

Studies on Performance and Mechanism of Negative Phototropism of Chlorophytum comosum Roots and Its Regulation

The aerial roots of Chlorophytum comosum were planted in water to grow hydroponic roots to study the negative phototropism performance and mechanism and its regulation.（1）All the adventitious roots and their branch roots bent away from light，the maximum curvature maybe 88.5°.（2）Photo perception site was root cap. The curvature was increasing when light intensity ranged from 0 to 110 μmol ? m-2 ? s-1. Blue-violet light induced the negative phototropism prominently while red light had no effect.（3）The negative phototropism curvature could be promoted by exogenous CaCl2，but inhibited by exogenous LaCl3，meanwhile，exogenous CaCl2 could relieve the inhibiting effect of LaCl3.（4）Unilateral light induced horizontal transport of IAA from the irradiated side to the shaded side which resulting in the unequal distribution of IAA in the both sides that led to the formation of negative phototropism. The horizontal transporting of IAA was promoted exogenous Ca2+ but inhibited by exogenous La3+.