Xanthophyli cycle has been widely concerned since the finding that it has the function in heat dissipation . with the trans - thylakoid ph gradient , zeaxanthin ( z ) together with antheraxanthin ( a ) can absorb excess energy from chlorophyll and release it as heat , thus protect the photosynthetic apparatus from photodamage by high light . violaxathin de - epoxidase ( vde ) is the key enzyme in xanthophylls cycle 目前普遍认为叶黄素循环的色素定位于天线色素蛋白复合体上，在跨膜质子梯度( ph )形成后，玉米黄质( z )和环氧玉米黄质( a )能够从叶绿素中吸收过多的激发能，并以热能的形式耗散到体外，从而保护光合器官免受强光的破坏。
In order to elucidate the physiological mechanism of carotenoid formation in citrus fruit , we determined a - carotene , p - carotene , lycopene , p - cryptoxanthin , zeaxanthin and lutein content in 53 varieties that belong to various citrus types using hplc , analyzed the possible connection between color formation and carotenoid accumulation , and studied the effects of light . ga3 and mpta on carotenoid biosynthesis in peel of citrus fruit . the results are summarized below 为探讨柑橘果实类胡萝卜素形成的生理机制，本论文运用hplc技术测定了我国宽皮柑桔类、橙类、柚类及杂柑类等不同柑橘类型共53个品种(系)的-胡萝卜素、 -胡萝卜素、番茄红素、 -隐黄质、玉米黄素、叶黄质六种类胡萝卜素的含量，分析了柑橘果实不同色泽的呈现与果皮类胡萝卜素积累的可能联系，并探讨了光照、 ga _ 3 、 mpta等不同处理对柑橘果皮类胡萝卜素形成的调控机制，主要结果如下： 1
