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近年来火龙果大面积在岩溶区种植,岩溶干旱是否对其生理过程产生影响,对于规划和管理这种热带水果具有重要科学意义。本研究通过试验对比研究火龙果及其近缘野化种量天尺的生理生化过程对不同水分水平的响应,阐明这两种植物的适应干旱机制。结果表明,两种植物随土壤水分下降生理生化变化过程基本一致。随着土壤干旱的加剧,有害物质丙二醛增加,但同时两种保护酶(SOD和POD)和渗透调节物质Pro也随之增加;在相对含水量>50%,保护酶能有效清除代谢毒素,Pro也能通过渗透调节维持水分需要;但是当相对含水量<40%时,保护酶的保护功能下降。叶绿素通过光合作用形成生物量,在相对含水量为70%-80%时生物量最大,此时根冠比小,地上生物量最大;土壤相对含水量为30%-40%时生物量显著下降,两种植物的降幅分别达到73.28%和73.56%。因此在岩溶地区发展火龙果,土壤水分控制在相对含水量为70%-80%为最佳,有利于水果产量的形成;中度水分不足,虽然植物通过代谢调节和平衡不利因素,但却分配较多的生物量到根系,降低地上生物量,从而不利于水果产量的形成。
In recent years, the large area of pitaya growing in the karst area, karst drought whether its physiological processes have an impact, for the planning and management of this tropical fruit has important scientific significance. In this study, we compared the physiological and biochemical responses of Pitaya and its related wild species to different water levels through experiments and compared them to clarify the mechanism of drought tolerance in both plants. The results showed that the physiological and biochemical changes of the two plants were basically the same as the soil moisture decreased. With the aggravating of soil drought, the content of malondialdehyde (MDA) increased, but at the same time, the two protective enzymes (SOD and POD) and osmotic adjustment substance Pro also increased. At the relative water content> 50%, the protective enzymes could effectively remove metabolic toxins , Pro can also maintain the water requirement through osmotic adjustment; however, the protective function of the protective enzyme decreases when the relative water content is less than 40%. Chlorophyll formed biomass through photosynthesis, biomass was the highest when the relative water content was 70% -80%, the root-shoot ratio was the smallest, and the aboveground biomass was the largest; the biomass decreased significantly when the soil relative water content was 30% -40% The decline of the two plants reached 73.28% and 73.56% respectively. Therefore, the development of pitaya in karst area, the control of soil moisture in the relative water content of 70% -80% for the best, is conducive to the formation of fruit production; moderate water shortage, although plants through metabolic regulation and balance unfavorable factors, but the distribution More biomass to the root system, reducing aboveground biomass, which is not conducive to the formation of fruit yield.