| Previous studies have shown the effects of climate change on the growth,photosynthesis,product distribution,yield and yield components of wheat in different temperature increasing modes and periods,and in different wheat producing areas.However,most of these studies focused on the morphological indicators and yield characteristics of wheat in loam or cotton soils,while few studies were reported on the growth of crops in saline-alkali soils and the utilization of nutrients in wheat.The purpose of this study was to explore the effects of climate warming on the growth and nutrient use efficiency of spring wheat in saline-alkali land of Ningxia,further clarify the effects of climate warming on the growth of spring wheat in arid and semi-arid regions,and finally provide theoretical basis for high-yield and high-efficiency cultivation of spring wheat in this climate condition.Using the method of automatic control of infrared radiator to simulate climate change,we set different temperature gradients(CK:0?,T1:0.5?,T2:1?,T3:1.5?,T4:2.0?)on the basis of canopy temperature of spring wheat without warming treatment.In 2017 and 2018,we conducted a study on the effects of temperature rise on the growth,leaf physiological characteristics,yield and quality of spring wheat in the saline-alkali land improvement experimental station of Ningxia university saline-alkali land improvement test station in Pingluo.The results show that:1?The increase of temperature accelerated the growth rate and shortened the growth period of spring wheat.The increase of temperature from seedling stage to jointing stage is 0.5?,which is beneficial to the growth of plant height and dry matter weight of spring wheat.If the increase of temperature is greater than 0.5? or the increase of temperature is longer than jointing stage,the increase of plant height and dry matter weight of spring wheat will be negatively affected.2?Effect of warming on physiological characteristics of spring wheat at different growth stages.With the increase of temperature from seedling stage to jointing stage of spring wheat at 0.5?,the soluble protein content,CAT(catalase),POD(peroxidase),SOD(superoxide dismutase)activity of leaves increased,while the membrane permeability,MDA(malondialdehyde)molar mass fraction and Pro(proline)mass fraction of leaves decreased,and most of the differences were significant.With the prolongation of the heating time and the increase of the temperature gradient the above indexes all show the opposite trend.With the increase of temperature from seedling stage to jointing stage of spring wheat at 0.5?.Leaf area,chlorophyll content,Pn(net photosynthetic rate)and WUE(water use efficiency)of spring wheat were higher than those of the control,which was beneficial to increase the potential activity of photosystem II and photosynthesis.Leaf area,chlorophyll content,Pn(net photosynthetic rate)and WUE(water use efficiency)of leaves decreased with the increase of temperature from 1.0 to 2.0?,but the decrease of Pn was mainly caused by stomatal factors.After jointing stage,the temperature of spring wheat increased by 0.5?2.0?,the photosystem ? reaction center of leaves was reversibly inactivated,while the leaf area,chlorophyll content,Pn(net photosynthetic rate),WUE(water use efficiency)decreased,and the photosynthetic apparatus was damaged.3?Effects of warming on nutrient use efficiency of spring wheat at different growth stages.The total N,P,K nutrient uptake,N,P,K nutrient content and nutrient accumulative uptake of shoot organs of spring wheat were significantly higher than those of the control at 0.5? before jointing stage.The accumulative N nutrient uptake and N,K content of seedling and leaf at jointing stage were significantly higher than those of the control at 1.0?.And the K content of seedling was significantly higher than that of the control at 1.5? only at seedling stage.The indexes above 2.0? were significantly lower than those of the control.After jointing stage,except for the difference of K content between the two groups was not significant at 0.5?,the other indexes were significantly lower than those of the control group.The larger the temperature gradient was,the larger the decrease range of each index was.4?The yield,spikelets,grains per spike and thousand grain weight of spring wheat were significantly lower than those of the control when the temperature was increased by 0.5?2.0?.The larger the temperature gradient was,the more the decrease was,and the more obvious the yield reduction was.The moisture content,amylose content,gluten content,stabilization time and flour quality index of spring wheat grain flour showed a significant downward trend,while the ash content and water absorption rate of flour showed a significant upward trend.Under warming conditions,plant height,dry matter weight,leaf Pn,Gs,N,P,K accumulative uptake of spring wheat were positively correlated with yield at all growth stages,most of them were significantly or very significantly positively correlated,while most of leaf Tr were significantly negatively correlated. |
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