增强紫外线-B辐射冬小麦产量和光合特性的影响

为了研究紫外线-B（ultraviolet-B UV-B, 280-320nm）辐射增强20%对保护性耕作冬小麦产量及光合特性的影响，在中国南京开展了2 a的田间试验研究。试验采用常规耕作（耕深25 cm）、少耕（耕深10 cm）和免耕（土壤不耕作）3种耕作处理种植冬小麦，采用人工增加紫外辐射的方法模拟UV-B辐射增强。试验测定了冬小麦旗叶的光合速率、光合-光响应曲线、叶绿素质量分数、超氧化物歧化酶（superoxide dismutase, SOD）活性、丙二醛（malonaldehyde, MDA）质量分数和可溶性蛋白质量分数等指标。结果表明：在UV-B辐射增强20%条件下，与常规耕作相比，少耕和免耕2种保护性耕作处理可显著提高冬小麦的产量，分别比常规耕处理作高1632.12和952.15 kg/hm2。从叶片光合生理特性来看，在UV-B辐射增强20%条件下，从冬小麦籽粒灌浆中期开始，少耕和免耕处理旗叶的光合速率、表观量子效率（apparent quantum yield, AQY）、最大净光合速率（Pmax）、叶绿素质量分数、SOD活性、可溶性蛋白质的质量分数显著高于常规耕作处理，MDA质量分数显著低于常规耕作处理，2种处理冬小麦的叶片衰老显著低于常规耕作处理。在UV-B辐射增强20%条件下，少耕和免耕2种保护性耕作处理冬小麦旗叶在籽粒灌浆中期及以后保持高的光合能力和低的衰老程度，是其产量高于常规耕作处理的原因。该文可为制定UV-B辐射增强条件下的冬小麦栽培措施提供参考。

Effects of enhanced ultraviolet -B radiation on yield and photosynthesis characterister of winter wheat

Abstract: Changes in the photosynthetic characteristics in winter wheat ( Triticum aestivum L.) flag leaf with different soil tillage methods under control and ultraviolet-B enhanced radiation (UV-B, 280-320nm) were investigated. The field experiment was carried out in Nanjing, China. It lasted two years. The experiment included three tillage methods: conventional tillage (moldboard plow, 25 cm of tillage depth), minimum tillage (rotary tillage, 10 cm of tillage depth), and no-tillage (0 cm of tillage depth) for wheat cultivation. Minimum tillage and no-tillage methods were conservation tillage methods. Artificial UV-B radiation was used to simulate the enhancement of UV-B radiation. The supplemental UV-B radiation was supplied with the UV-B lamps (40 W, peak of lightwave is 313 nm). The level of UV-B irradiance supplemental was equivalent to an enhancement of 20% above the control treatment. The photosynthetic rate, photosynthesis - light response curve, chlorophyll content, superoxide dismutase (SOD) activity, malonaldehyde (MDA) content, and soluble protein content in winter wheat flag leaf were determined in the experiment. The results showed that: Under the 20%-enhanced UV-B radiation condition, the yield of winter wheat for minimum tillage and no-tillage methods increased by 1632.12 and 952.15 kg/hm2, respectively, both significantly higher than that of the conventional tillage method. Analyzing from the photosynthesis, the photosynthetic rate, apparent quantum yield (AQY), maximum photosynthetic rate (Pmax), chlorophyll content, SOD activity and soluble protein content of flag leaf for minimum and no-tillage methods were significantly higher than that of the conventional tillage method, but the MDA content was lower at 15 days after wheat anthesis, and the senescence degree of wheat flag leaf was significantly lower than that of the conventional tillage method. It was considered that the higher photosynthetic capacity and lower senescence degree of wheat leaves during grain-filling period of two conservation tillage methods was a key reason for their higher yield than that of the conventional tillage method.