Effects Of Basic Plantling Density On Water And Photosynthetic Characteristics In Wide-Range Sowing Of Wheat

The experiment was conducted in the 2018-2020 wheat growing season at the Academician Experimental Station of Shijia Wangji Village,Xiaomeng Town,Yanzhou District,Jining City,Shandong Province（35°24’N,116°24’E）.Jimai 22 was used as the test material.Under the condition of wide sowing with a sowing width of 8 cm,set 0.90×10⁶plants·ha^-1（D1）,1.80×10⁶plants·ha^-1（D2）,2.70×10⁶plants·ha^-1（D3）,3.60×10⁶plants·ha^-1（D4）4 basic seedling density treatments were used to study the effect of basic seedling density on the water and photosynthetic characteristics of wide-sown wheat.The results are as follows:1 Effects of basic planting density on water consumption characteristics in wide-rang sowing of wheatUnder the wide-range sowing conditions,the irrigation amount and total irrigation amount during jointing and anthesis period of D2 treatment were significantly lower than that of D4 and D3 treatments.The proportion of total water consumption and soil water consumption in growth period to total water consumption was significantly lower than that of D3 and D4 treatment;soil water consumption of 140～200 cm soil layer was significantly higher than other treatments;soil water consumption from jointing to anthesis,water consumption from jointing to anthesis,and water consumption modulus were significantly higher than other treatments.It shows that D2 treatment is beneficial to improve the utilization of deep soil water by wheat,reduce the total water consumption during the growth period,and save irrigation water.2 Effects of basic planting density on photosynthetic characteristics in wide-rang sowing of wheatUnder the wide-range sowing conditions,the flag leaf net photosynthetic rate,transpiration rate,and stoma conductance of the D2 treatment 7～21 days after anthesis were significantly higher than other treatments;7 days after anthesis,the canopy leaf area index,photosynthetic active radiation interception rate,and interception were significantly higher,light energy utilization,flag leaf sucrose content and sucrose phosphate synthase activity were significantly higher than other treatments;dry matter accumulation during anthesis and maturity,dry matter distribution in the grain after anthesis and its contribution to the grain.The rates are also significantly higher than other treatments.It showed that D2 treatment was beneficial to improve the photosynthetic capacity of flag leaves and the carbohydrate synthesis capacity of flag leaves in the middle and late filling stage,prolong the holding period of flag leaves,and promote the distribution of dry matter accumulation to the grains during the mature period.3 Effects of basic planting density on flag leaf senescence characteristics in wide-rang sowing of wheatUnder the wide-range sowing conditions,the flag leaf superoxide dismutase activity and soluble protein content of the D2 treatment were significantly higher than other treatments from 7 to 14 days after anthesis;the flag leaf malondialdehyde content of the D2 treatment was significantly lower than other treatments.It shows that D2 treatment is beneficial to improve the scavenging ability of superoxide free radicals in flag leaves and reduce the damage of cell membrane structure,and delay the senescence of flag leaves.4 Effects of basic planting density on nitrogen utilization in wide-rang sowing of wheatUnder wide-range sowing conditions,the dry matter accumulation of D2 treatment during anthesis and maturity was significantly higher than that of other treatments;nitrogen accumulation in mature grains,nitrogen transfer from vegetative organs to grains after anthesis,and their contribution to grains The rates were significantly higher than other treatments.It shows that D2 treatment is beneficial to the accumulation of nitrogen in the mature stage of wheat and promotes the accumulation of nitrogen in the grain during the mature stage.The content of soil nitrate nitrogen in the 0～60 cm soil layer of D2 treatment was significantly higher than other treatments,and the content of soil nitrate nitrogen in the soil layer 60～160 cm was significantly lower than other treatments.It shows that D2 treatment is beneficial to the absorption and utilization of soil nitrate nitrogen by wheat,and reduces the leaching of soil nitrate nitrogen into deep soil.5 Effects of basic planting density on the physiological characteristics of the root system in wide-rang sowing of wheatUnder the wide-range sowing conditions,the dry root weight,root length,root surface area,root superoxide dismutase activity,and soluble protein content of 0～40 cm soil layer in the 0～40 cm soil layer of D2 treatment anthesis and 10 d after anthesis were significantly higher than other treatments.The content of MDA in 0～40 cm soil layer of D2 treatment was significantly lower than other treatments atanthesis and 10 d after anthesis.It shows that D2treatment is beneficial to improve the antioxidant capacity of wheat roots,delay root senescence,and promote the absorption and utilization of soil moisture and nutrients by roots.6 Effects of basic planting density on the grain yield and water use efficiency in wide-rang sowing of wheatUnder the wide-range sowing conditions,the number of grains per panicle and 1000-grain weight in the D2 treatment were significantly higher than those in the D3 and D4treatments;the grain yield and water use efficiency were significantly higher than other treatments.It shows that D2 is the best treatment for water saving and high yield under the experimental conditions.