Effects Of Intercropping On Rice-wheat Growth,Physiological Properties And Grain Quality Under Nighttime Warming

The increase in temperature at night is greater than the daytime is one of the main characteristics of climate warming.The effect of nighttime warming on rice and wheat production has received more attention.Mixed planting can increase rice production.However,it is unclear regarding the interaction between nighttime warming and mixed planting on rice production.Field experiments were conducted to study the effects of mixed planting on the growth,physiology and quality of rice and wheat under nighttime warming.The warming treatment was set at two levels,i.e.nighttime warming?NW?and control?CK?.Mixed planting was set at two levels,i.e.mixed cultivation?M,main planting variety:mixed planting=3:1?and single cultivation?S?.Rice was selected from Nanjing 9108?main plant?and hybrid rice Shenliangyou 884?second plant?.Winter wheat was selected from Zhenmai12?main plant?and Sumai 188?second plant?.The main results are as follows:?1?Growth of rice and winter wheatIn this paper,nighttime warming increased the average nighttime temperature of rice canopy in mixed cultivation and single cultivation by 1.06?and 0.46?,respectively.The average nighttime temperature of the 5 cm soil increased by 0.58?and 0.26?,respectively.The nighttime warming increased the average nighttime temperature of wheat canopy in mixed cultivation and single cultivation by 1.58?and 1.26?,respectively,and the average nighttime temperature of 5cm soil increased by 1.00?and 0.88?,respectively.Nighttime warming significantly reduced the plant height,SPAD value,dry weight of each part?dry leaf,dry stemt,dry panicle,dry root and total biomass weights?.Mixed cultivars significantly increased the plant height,SPAD value,dry weight of each part.Night temperature increase increased winter wheat plant height and SPAD value,dry weight of each part.Mixed cultivars also increased winter wheat plant height,SPAD value,dry weight of each part.?2?Photosynthesis and chlorophyll fluorescence of rice and winter wheatWith nighttime warming treatment,the net photosynthetic rate,transpiration rate,stomatal conductivity,and water use efficiency of rice in the main growth stages?tillering stage,jointing stage,filling stage,and maturity stage?rice were all reduced,but intercellular CO₂ concentration increased,and Mixed cultivars increased the net photosynthetic rate,transpiration rate,stomatal conductivity,intercellular CO₂ concentration,and water use efficiency of rice leaves.During the rice filling stage,nighttime warming reduced the leaf performance index and driving force,and mixed cultivars increased the performance index and driving force.The interaction between the two increases the performance index and driving force.With nighttime warming treatment,the net photosynthetic rate,transpiration rate,stomatal conductivity,and water use efficiency of the main growth stages?joining stage,heading stage,flowering stage,and filling stage?of winter wheat were increased,and intercellular CO₂ concentration was reduced.Mixed cultivars increased the net photosynthetic rate,transpiration rate,stomatal conductivity,intercellular CO₂ concentration,and water use efficiency in the main growth stages of winter wheat.During the winter wheat filling stage,nighttim warming and mixed cultivars both reduced the winter wheat leaf performance index and driving force,but the reduction was reduced under the interaction of the two.?3?The quality of rice and winter wheat qualityThe nighttime warming and mixed cultivars have the potential to improve rice and wheat quality.Nighttime warming significantly reduced effective panicles,filled grain numbers per panicle,1000-seed weight and maturing rate of rice,which eventually led to a decline in yield.With nighttime warming treatment,the amylose content,total starch content,protein content and amylopectin content,brown rice rate,polished rice rate and whole polished rice rate of rice were all reduced.Mixed cultivars significantly and yield composition of rice,which eventually led to increased yield,and rice quality parameters were increased.Nighttime warming increased winter wheat yield and yield composition of each part and increased the total starch content,protein content,and amylopectin content of winter wheat,and reduced the amylose content and the amylose/amylopectin ratio.With mixed cultivars treatments,the yield and yield composition of winter wheat increased,the amylose content and protein in winter wheat increased,and the total starch content,amylopectin content,and amylose/amylopectin ratio changed in different degrees.