紫外-B辐射对番茄幼苗生长、POD和IAA氧化酶活性的影响

Effects of enhanced ultraviolet-B radiation on growth, POD and IAA oxidase activities in tomato seedling

模拟兰州地区夏季臭氧层减薄12%和20%时增强的UV-B辐射2.54kJ·m-2·d-1 T1 和4.25kJ·m-2·d-1 T2 ,以自然辐射为对照,研究2种辐射对番茄幼苗生长、叶绿素和可溶性蛋白质含量以及过氧化物酶 POD 、吲哚乙酸氧化酶 IAA氧化酶 活性的影响.结果表明:低强度、短时间的辐射 T1,10d 对番茄幼苗生长没有影响,而高强度、长时间的辐射可减少生物量累积,降低株高、壮苗指数、叶绿素a、b和总叶绿素的含量,对叶绿素a/b无显著影响;与对照相比,可溶性蛋白质含量在辐射处理10d和20d时均减低,40d时升高;T2处理使POD活性一直显著高于对照;IAA氧化酶活性在辐射10d和20d时增加,40d时显著低于对照.说明在UV-B辐射下光合下降、IAA分解抑制了番茄幼苗的生长.

The growth, chlorophyll and soluble protein contents, the activities of POD and IAA oxidase were studied in tomato seedlings grown in glasshouse condition irradiated with ambient(CK) , 2.54 kJ·m^(-2)·d^(-1) (T1) and 4.25 kJ·m^(-2)·d^(-1) biological effective UV-B radiation (stimulating a 12% and 20% reduction in stratospheric ozone at Lanzhou, respectively). The results indicated that the growth were unaffected under low dosage and short time treatment with UV-B radiation, but biomass accumulation, plant height, the index of stronger seedlings, chlorophyll a,chlorophyll b and total chlorophyll and soluble protein contents were reduced , the activities of POD and IAA oxidase were increased under high dosage and long time treatment with UV-B radiation. The ratio of chlorophyll a/b was not affected. Compared with control, the contents of soluble protein decreased after 10 d and 20 d and increased after 40 d radiation in both treatments. The POD avtivity was higher in irradiated seedlings by T2 treatment than that control. The IAA oxidase activity rised after 10 d and 20 d treatment but reduced after 40 d UV-B radiation. The results of this studies showed the inhibited growth in tomato seedling grown both UV-B radiation was due to the reduction of photosynthesis and decomposition of IAA.