摘要
研究了0.4w·m-2的紫外线-B(UV-B)辐射对0.8%NaCl胁迫下冬小麦"小偃926"(TriticumaestivumL.xiaoyan-926)幼苗的生长、光合作用、水分状况、黄酮含量和膜脂过氧化等几方面的影响。结果表明,UV-B辐射和NaCl胁迫单独或复合处理下小麦幼苗的株高、生物量、含水量、净光合速率、蒸腾速率、气孔导度和光合色素含量均显著降低,膜脂过氧化产物丙二醛含量和叶片相对电导率则升高,但NaCl胁迫条件下增加UV-B辐射(复合处理)与单独NaCl胁迫相比,上述指标多数均无显著差异(除复合处理下类胡萝卜素含量显著降低外)。两胁迫因子单独或复合处理均明显提高了小麦幼苗黄酮含量及三种抗氧化酶(SOD、POD和CAT)活性,且复合处理的促进效应最大。脯氨酸含量在单独UV-B辐射下明显降低,在单独NaCl胁迫和复合处理下显著升高,且复合处理下增幅最大。结果说明UV-B辐射不会明显加剧NaCl胁迫下小麦幼苗的伤害,这可能与NaCl胁迫提高了小麦幼苗黄酮含量、脯氨酸含量和抗氧化酶活性有关。
The depletion of the stratospheric ozone layer has been well documented, so ultraviolet-B (UV-B) radiation (280～320 nm) reaching the earth surface has increased since 1970s. Although extensive studies were done about biological and ecological effects of enhanced UV-B radiation, little was known about the interactive effects of UV-B radiation and NaCl stress on plants. In this paper, the interactive effects of UV-B radiation (0.4 w·m^(-2)) and NaCl stress (0.8%) on growth, photosynthesis, water status, flavones and activities of antioxidative enzymes in wheat ( Triticum aestivum L. Xiaoyan-926) seedlings were studied. Four treatments were included in the experiment: no addition of NaCl and no exposure to UV-B radiation (CK), addition of NaCl (NaCl), exposure to UV-B radiation (UV-B), addition of NaCl and exposure to UV-B radiation (UV-B+NaCl). The addition of NaCl was started after 3 days of seedling growth, the UV-B radiation was started to supply in photoperiod after 10 days of seedling growth. The seedlings were grown at 30/25℃ (day and night) and 75% relative humidity with a 11 h photoperiod under fluorescent white light (300～350 μmol·m^(-2)·s^(-1)) in a greenhouse. All measurements were made at 20 day of seedling growth. The results showed that treatments of UV-B, NaCl and UV-B+NaCl all resulted into a decrease in plant height, biomass, water content, net photosynthetic rate, transpiration rate, stomatal conductance and contents of photosynthetic pigments, and into an increase in relative leakage ratio and lipid peroxidation, as quantified by measurement of malondialdehyde (MDA). However there were not significant differences in most of above parameters between NaCl and UV-B+NaCl treatments (not including carotenoid content). Contents of flavones and activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) increased obviously under all stress conditions, but the increasing was mostly induced by UV-B+NaCl treatment. Proline content was reduced by UV-B treatment and enhanced by NaCl and UV-B+NaCl treatments, but the effect of UV-B+NaCl treatment was bigger than that of NaCl treatment. These results indicated that UV-B radiation did not obviously strengthen the inhibition of wheat seedlings induced by NaCl stress, this may be related to the results that NaCl stress induced the enhancement of contents of flavone and proline and activities of SOD, POD and CAT in wheat seedlings.
出处
《西北植物学报》
CAS
CSCD
2004年第10期1810-1815,共6页
Acta Botanica Boreali-Occidentalia Sinica
关键词
UV—B辐射
NACL胁迫
小麦幼苗
生理生态特性
UV-B radiation
NaCl stress
wheat seedlings
physiological and ecological properties
