不同土壤温度对玉米苗期根系构型的影响OA北大核心CSTPCD

To investigate the impact of different soil temperatures on the growth and development of maize seedlings,a study was conducted using'Zhengdan 958'as the experimental material,five soil temperatures of 25.0(CK),27.5(T1),30.0(T2),32.5(T3)and 35.0(T4)℃ were set at the seedling stage of maize,respectively.The increased temperatures lasted for 10 d.The characteristics such as root morphology,topology,and root conformation at each diameter level were determined in maize seedlings.The results showed that compared with the soil temperature of 25.0 ℃(CK),the soil temperature treatment of 27.5 ℃ significantly increased the length,surface area,volume,number of branches,number of root tips and fractal dimensions of the maize seedling stage;with the continuous increase of the temperature,the temperature increase gradually produced a significant inhibition of root growth and development,and the above six indexes were significantly reduced when the soil temperature reached 35.0 ℃.When the soil temperature was＜30.0 ℃,the elevated soil temperature led to a significant increase in the length,surface area and volume of fine roots(≤0.5 mm)as a proportion of the total root system,and at the soil temperature of 30.0 C,the length,surface area and volume of fine roots accounted for 84.00％,64.79％ and 31.89％ of the total root system,respectively.When the soil temperature increased to 35.0 ℃,the percentage of fine root length,surface area and volume decreased significantly,while the percentage of medium roots(0.5-1.0 mm)and thick roots(＞1.0 mm)increased significantly.At 27.5 C,the shoot dry weight of 0.887 8 g and the root dry weight of 0.460 5 g at maize seedling reached a significant maximum,and the root-shoot ratio also reached a minimum of 0.474 7.By fitting the soil temperature and maize seedling characteristics,it was concluded that the soil temperature of 27.3-28.7 ℃ was suitable for the growth of maize seedling.In conclusion,when the soil temperature was 25.0-30.0 ℃,with the increase of soil temperature,the root system of maize seedlings lengthened,the percentage of fine roots increased,and the dry weight of plants increased,while maintaining a low root-shoot ratio;when the soil temperature was ≥30 ℃,the growth of maize root system was restricted,and the percentage of fine roots of maize seedlings decreased,while the root-shoot ratio increased.When the soil temperature reached 35.0 C,the growth of maize seedlings was seriously affected.