贵州辣椒光合生理特性对干旱胁迫的响应

辣椒是贵州省特色经济作物之一,是农业产业结构调整的主导和优势产业,但贵州省大部分地区属喀斯特地貌,土壤保水性差,极易发生干旱,探明辣椒在干旱胁迫处理后的调节机制和变化规律,对实现贵州地区辣椒优质高产有重要的理论价值和实际生产意义。选取贵州省辣椒主栽品种辣丰三号,研究以土壤田间持水量80%为对照组（CK）,在轻度（土壤田间持水量为70%,LD）、中度（60%,MD）、重度（40%,SD）和特重（20%,TD）胁迫下,辣椒的产量、生长量、光合特性和果实生理特性的调节机制和变化规律。结果表明,随着干旱胁迫程度的增加,辣椒的果长、果粗、茎粗、株高、单果重以及干物质含量显著下降,且下降趋势随着干旱胁迫程度的增加越加明显。同一处理辣椒的净光合速率（P_n）表现出先上升后逐渐平稳的趋势,随着干旱程度的增加而逐渐降低,最大净光合速率（A_max）、表观量子效率（Q）、气孔导度（G_s）、胞间CO₂浓度（C_i）和蒸腾速率（T_r）都显著下降,水分利用效率明显上升。干旱胁迫抑制了辣椒植株的生长,辣椒的粗脂肪和粗纤维含量较CK处理显著下降,LD处理二氢辣椒素含量显著低于CK处理,但是随着干旱程度的增加,辣椒素和二氢辣椒素含量逐渐增大（除LD和TD处理外）。综上可知,在贵州喀斯特干旱地区,轻度至中度干旱胁迫（田间持水量60%~

Response of Photosynthetic Physiological Characteristics of Pepper in Guizhou under Drought Stress

Pepper is one of economic crops in Guizhou, agricultural structure coordination province, which is the leading and influential industries. Most areas in Guizhou belong to karst landforms, poor soil water retention which are prone to drought. It is important to clarify the drought resistance mechanism of pepper which has important theoretical value and practical production significance for realizing the quality and high yield of pepper production in Guizhou. The main pepper variety Lafeng No.3 in Guizhou province was selected for this experiment to study the yield, growth, photosynthetic characteristics and regulation mechanism, and variation law of fruit physiological characteristics of pepper under light (LD), moderate (MD), severe (SD) and extremely severe (TD) drought stress (field water capacity was 70%, 60%, 40% and 20%). With the increase of drought stress, the fruit length, fruit thickness, stem thickness, plant height, single fruit weight, and dry matter content of pepper plants decreased significantly and the decreasing trend became more obvious with the increase of drought stress. Pepper's net photosynthetic rate showed a trend of rising first, then gradually stabilized, and finally gradually decreased with the increase of drought. The maximum net photosynthetic rate, apparent quantum efficiency, stomatal conductance, intercellular CO₂ concentration, and transpiration rate all decreased significantly. However, water use efficiency increased significantly. Drought stress inhibited the growth of pepper plants, and the contents of crude fat and crude fiber of pepper decreased significantly. Under LD, the contents of dihydrocapsaicin were significantly lower than those of the control group. While, with the increase of drought stress, the contents of capsaicin and dihydrocapsaicin gradually increased (except LD and TD treatments). In conclusion, in the Karst arid area of Guizhou, mild to moderate water stress (field water capacity 60%-70%) could meet the normal growth requirements of pepper.