低温对豌豆幼苗生理特性和超微结构的影响

Effect of Low Temperature on the Physiological Characteristics and Ultra-structure of Garden Pea Seedling

[目的]探索豌豆抗寒的生理特性,为扩大引种栽培提供科学依据。[方法]豌豆种子在25℃下浸种24 h后暗培养,待胚根长到3～4 cm时,转入10℃下继续暗处理2 d,取近子叶端的下胚轴,测定细胞可溶性糖和(丙二醛)MDA含量、电解质外渗率以及抗氧化酶活性,并观察细胞的超微结构变化。[结果]从生理特性看,10℃低温后,除POD活性略有下降外(P>0.05),豌豆幼苗细胞其他指标均不同程度上升,其中SOD活性显著(P<0.05)升高。从超微结构看,10℃低温后,质膜出现凹陷、外凸、质壁分离以及波浪状等现象;中央大液泡、内质网、高尔基体和细胞质等多处结构形成小液泡,小液泡聚集或分散出现在细胞质中或大液泡内,或质膜和细胞壁间;细胞质内出现多种变形质体,有哑铃形、变形虫形、马蹄形、镰刀形、棒状等。[结论]豌豆幼苗细胞具有较强的抗寒性,并能从提高细胞质或细胞液浓度、增加质膜的透性、保证能量的供给等方面对10℃低温产生积极的防御作用。

[ Objective ] The scientific basis of the introduction and cultivation of garden pea was provided through the research on the its physiological characteristics in cold-resisting. [ Method] The pea seedling with 34 cm radicle,which seeds were cultured in dark room after soaked for 24 hours at 25 ℃ ,was transferred for its continually culturing in the dark room at 10 ~C for two days. And then,the content of soluble sugar and MDA,the ratio of electrolyte leakage and the activity of antioxidant enzyme in the hypocotyls cell close to cotyledon were determined and the ul- tra-structural of the cell was observed. [ Results ] From the view of physiological characteristics,all of indexes, except for a slight downward trend in the activity of POD （P 〉 0.05 ） ,were increased to varying degrees after garden pea seedling was cultured in the low temperature of 10℃ ,among which,the activity SOD was significantly（ P 〈 0.05 ） increased. From the view of ultra-structure, after garden pea seedling was cultured in the low temperature of 10℃ ,the phenomena such as the depression,convex, plasmolysis and wave-like on the plasma membrane appeared; the multiple small vacuoles were formed in central large vacuole, endoplasmic reticulum, golgiosome and cytoplasmic and those small vacuoles were clustered or dispersed in the cytoplasm,or in large vacuole, or plasma membrane and cell wall, respectively. A variety of deformation plastids like dumbbell-shaped ,amoeba-shaped ,U-shaped ,sickle-shaped ,rod-shaped and so on occurred in cytoplasm. [ Conclusion ] The garden pea seedling cells were with a strong resistance to cold and the positive defensive role of it to low temperature of 10 ℃ was from the increment of concentration of cytoplasm or cell sap,the strength of the permeability of plasma membrane for the supply of energy.