文心兰不同生育期茎叶生理指标的动态变化

Physiological Indices on Top-leaves and Pseudo-bulbs of Oncidium at Different Growth Stages

以3年生文心兰‘金辉’为试验材料,测定其4个不同生育期顶叶和假鳞茎中叶绿素、相对电导率、可溶性糖、还原糖、淀粉、脯氨酸(Pro)和过氧化物酶(POD)等生理指标。结果表明:膨大期顶叶叶绿素含量最低,而相对电导率则最高,两者随后趋于稳定。不同时期假鳞茎中可溶性糖、还原糖及淀粉的含量均高于顶叶;可溶性糖含量均先升后降,在成熟期时最高;顶叶中还原糖含量先降后升,在假鳞茎中呈升降升的变化趋势,分别在膨大期和成熟期时最高;淀粉含量均先升后降,在侧芽期时最高。Pro含量、POD活性均呈先降后升的变化趋势,在成熟期和侧芽期时较低,在膨大期和子茎期时较高。

Changes on the physiological indices including chlorophyll,relative conductivity,soluble sugars,reducing sugars,starch,proline and POD on the top-leaves and pseudo-bulbs of 3-year-old Jinhui orchid,Oncidium,at different growth stages were monitored.It was found that the chlorophyll content in the top-leaves was the lowest,while the relative conductivity highest,at the expanding stage of the plants.They stabilized subsequently.The contents of soluble sugars,reducing sugars and starch in the pseudo-bulbs were higher than those in the top-leaves.Soluble sugars in both tissue parts increased initially,then decreased,and reached a peak at maturation.The reducing sugars in the top-leaves decreased in the beginning followed with an upward trend.Whereas,in the pseudobulbs,the content increased at first,then decreased,and followed by an increase,with two separate peaks occurred at the expanding and maturation stages.Starch in the top-leaves and the pseudo-bulbs increased at first,maximized at the lateral bud stage,then declined.In the beginning of the plant growth,both proline content and POD activity decreased,but increased afterward.The POD activity was low at maturation and lateral bud stages,while high at expanding and pseudo-bulb off-shooting stages.