Study On Photosynthetic Characteristics And Fruit Growth Of Different Walnut Varieties

In this experiment,four walnut varieties'Xiangling','Zha343','Jinxiang'and 'Zhonglin No1'in Jiaocheng County of Shanxi Province,were used as materials.In this paper,the dynamic changes of photosynthetic characteristics and nutrient components in the leaves of the nucleus were studied,and the dynamic changes of appearance characters,fruit yield and nutrient content of walnut fruit in the middle and late stages of development,in order to determine the best walnut varieties for reference,to provide further theoretical basis for high yield and high yield of walnut in Jiaocheng County,Shanxi Province.The findings are as follows:(1)The seasonal variation of net photosynthetic rate of 4 walnut varieties showed a single peak curve,'Zha 343'was at the highest level;The diurnal variation of net photosynthetic rate showed a bimodal curve,and there was a lunch break' phenomenon.The order of the maximum daily net photosynthetic rate from big to small is' Zha 343'>'Zhonglin No.1'>'Jinxiang'>'Xiangling'.The net photosynthetic rate of four walnut varieties increased first and then decreased with the increase of light intensity,there were significant differences between the light saturation point and the maximum net photosynthetic rate of leaves,the order from big to small is' Zha343'>JinXiang'>'Xiangling'>'Zhonlin No.1';The apparent photosynthetic electron transfer rate(ETR)of the four walnut cultivars was significantly correlated with the actual primary light energy trapping ability(PhiPS II).The initial fluorescence F0 was negatively correlated with the primary light energy conversion efficiency(Fv/Fm),the actual primary energy trapping ability(PhiPS II)and the apparent photosynthetic electron transfer rate(ETR).The leaf specific leaf weight and chlorophyll content of 4 walnut cultivars increased first and then decreased with the seasonal variation;The starch content in leaves of walnut varieties in different periods showed a decreasing trend,the starch content was the lowest after fruit ripening.The total soluble protein content decreased firstly and then increased with the seasonal change,which reached its lowest level on July 22nd,the content of soluble sugar increased first and then decreased with the seasonal change,and then remained unchanged.The mineral content of walnut leaves showed an increasing trend of mg content,the growth rate of Ca element was accelerated in the later stage of fruit maturation,and the difference of K element in different varieties was not obvious after fruit ripening.The content of Fe changed greatly,and the biggest decrease of Fe content among different varieties was' Jinxiang',which increased from 110 mg/Kg to 55 mg/kg;the content of Zn decreased during the whole ripening cycle of walnut kernel.The content of mn decreased first and then increased during the whole growth cycle,and reached its highest point on September 17.(2)The shell features of 4 varieties are mainly oblong,the shell is more smooth,the inner seed coat is mostly yellow,the nucleoli are full,and the kernels are easy to take.'Zha 343' is the largest of 47.34mm in the third path of green fruit and nut.The highest yield per plant of'Zha 343'is 7941.50g/zhu.In the correlation analysis,the mean value of three paths of green peel was significantly correlated with fresh weight,single fruit weight and kernel weight,and the fruit weight was significantly correlated with kernel weight,and the kernel weight was negatively correlated with shell thickness.(3)During the middle and late growing period of 4 walnut varieties,the moisture content of nut decreased generally,on June 24,walnuts had the highest water content,gradually leveled off at maturity.The soluble protein and total soluble sugar of nucleolus were increasing as a whole.The content of crude fat in the middle and late stages of fruit growth among different walnut varieties is generally upward trend,After fruit development and maturation,the fruit maintained a steady growth,and showed a rapid growth trend from June 24 to September 5.During the middle and late growing period of 4 walnut varieties,the content of Zn in nucleolar kernels fluctuated greatly during the whole ripening period of walnut kernel,but the content of Zn increased in general.The content of Mn increased first and then decreased in the whole mature period,reaching the highest point in September 9th.The Fe content changed greatly,from 66.8 ?g/g to 360.8 ?g/g,increased 5.4 fold.The contents of K and Ca elements in the middle and late stages of fruit development are basically the trend of gradual increase,and there is little difference among different varieties in K element.The difference of Ca content among different varieties was significant,which increased obviously from June 24 to September 5,and remained unchanged at the later stage of fruit ripening,and the growth rate was slow.The Ca content of 'Jinxiang' cultivars was higher than that of different cultivars,and the content of mg remained basically unchanged in the middle and late stages of fruit development,and most of the contents remained between 1 lmg/g-15mg/g.Synthesizing the above analysis,Among the 4 varieties tested,'Zha 343' had higher photosynthetic capacity,high yield,suitable for popularizing and planting.