Physiological Mechanism of the Response of Piper nigrum L.Seedlings to High-Temperature Stress in the Soil
Plants of the main pepper variety Reyin 1 were used as test materials,and five soil temperature gradients of 25,30,35,40,and 45 ℃ were used to study the effects of high-temperature stress in the soil on the growth of pepper seedlings and explore their response mechanism.The results revealed that with increasing soil temperature,the degree of stress on pepper seedling growth gradually increased,and the effect of stress on root growth became more distinct.Compared with those in the control treatment(25℃),the aboveground biomass indicators decreased significantly at 40℃ and above.However,the total root length,root number,root surface area,and other indicators decreased significantly at 30℃.The net photosynthetic rate,stomatal conductance,transpiration rate,etc.,of leaves,declined significantly with increasing soil temperature after the soil temperature reached 35℃ and reached the lowest value at 45℃;however,the MDA content(MDA)in the roots increased significantly with increasing soil temperature.At 35℃,the MDA content increased significantly,102.06％higher than that at 30℃,indicating that this soil temperature stress caused great harm to the roots,causing a large amount of peroxide to be gen-erated and accumulate in the root cells.Peroxidase(POD)activity increased with increasing soil temperature,but the changes in catalase(CAT)and superoxide dismutase(SOD)activities were not consistent,implying that with increasing degrees of stress,the types and activities of enzymes involved in response to stress at different stages differ,and the combined effects play a beneficial role in protecting the plant.Owing to high-temperature stress in the soil,nutrient absorption by pepper seed-lings is also affected.The ability of plants to absorb phosphorus was significantly limited.Therefore,in actual production,appropriate measures should be taken to reduce the soil temperature according to the soil temperature in the field and create a good pepper root growth environment to promote plant growth.
万方数据
维普
