Effects Of Low Temperature At Flowering Stage Flowering And Fruiting Characteristics Of Peanut

As one of the most important periods in peanut growth,flowering period has an important impact on seed setting.As the northernmost peanut area in China,the breadth and intensity of low temperature in flowering period are high,which has a certain impact on peanut yield.Exploring the response law of peanut flowering characteristics to low temperature at flowering stage and its impact on final yield has far-reaching field guiding significance.In this experiment,five types of peanut varieties were used,and three temperature conditions were set: low temperature treatment(20 ℃ in the day and 15 ℃ in the night)(L),medium temperature treatment(25 ℃ in the day and 20 ℃in the night)(ML)and normal temperature treatment(30 ℃ in the day and 25 ℃ in the night)(CK).Peanut potted plants were treated at the flowering stage,and the effects of low temperature on peanut flowering characteristics,dry matter,anther physiology and yield were systematically studied,in order to provide a theoretical basis for peanut low temperature tolerance production in the field.The main results are as follows:1.Through low temperature treatment in flowering period,the overall flowering time of peanut prolonged,the overall flowering number reduced slightly,and the flowering number within 14 days greatly reduced.The flower organs also shrink at low temperature,and the width of the wexillum,the height of the wexillum,the length of the calyx tube,the length of the anther and the width of the anther all decrease,among which the length of the calyx tube is the most significant.After the temperature is restored,the flower organs gradually recovered.In the indexes investigated,compared with the control,the effect of medium temperature treatment(ML)is slightly smaller than that of low temperature treatment(L).Different types of peanut varieties have different characteristics,and their low temperature performance at flowering stage is slightly different.2.Low temperature treatment at flowering stage had little effect on peanut anther cracking rate,and the cracking rate recovered rapidly after temperature recovery.Pollen viability is sensitive to low temperature.Low temperature lead to a significant decline in peanut pollen viability,and after the temperature is restored,the recovery speed of pollen viability is relatively slow,and even the recovery is difficult to reach the control level.After low temperature,the ultrastructure of peanut pollen was loose,the surface atrophied and the germination ditch was abnormal.The stigma is shortened after low temperature,and the phenomenon of short style appears.Similarly,in the indexes investigated,compared with the control,the effect of medium temperature treatment(ML)is slightly smaller than that of low temperature treatment(L).3.After low temperature treatment at flowering stage,the dry matter accumulation of peanut is affected by low temperature.Compared with the control,the low temperature degree of medium temperature treatment(ML)is relatively light and has less impact,while the low temperature degree of low temperature treatment(L)is relatively heavy and has a greater impact.Peanut varieties of different ecological types have different characteristics,and the effect of low temperature on dry matter accumulation is slightly different.4.Under the condition of low temperature in flowering stage,the contents of SOD,POD and CAT in anthers are increased in varying degrees.Under ML condition,the increase of antioxidant enzyme activity is less,under L condition,the increase of antioxidant enzyme activity is larger,and the difference of enzyme activity among three treatments reaches a significant level.5.The influence of low temperature on peanut flowering characteristics eventually lead to the change of peanut pod setting characteristics and ultimately affect the yield.Under the condition of low temperature in the flowering period,the pollen vitality is weak,the flowering is delayed,the number of pods per plant is reduced,the number of full pods per plant is also reduced,and the number of empty pods per plant is increased,which leads to the decline of peanut yield per plant.