Effect Of Zinc On The Growth And Fruit Quality Of Pecan

Zinc(Zn)is a necessary trace element for plant growth and plays an important role in various physiological and biochemical processes.Pecan is highly sensitive to zinc deficiency.Zinc deficiency will damage the roots,stems,leaves and other organs growth and development,reduce yield and quality.In order to grasp the dynamic changes of Zn uptake and transport of hatchback,the relationship between zinc and tree growth and photosynthetic characteristics.Grafted seedlings and seedling of pecan were used as test materials.The physiological and biochemical changes of pecans were studied under artificial cultivation conditions and zinc treatment.The main findings are as follows:The results showed that the mean contents of total zinc and available zinc in 0-20 cm soil layer were 104.81 mg/kg,2.72 mg/kg and 20-40 cm soil layers,respectively.The results showed that the content of total zinc and available zinc in 0-20 cm soil layer were 104.81 mg/kg,Zinc and available zinc content of the mean were 112.94 mg/kg,1.42 mg/kg.The average content of zinc in each organ was: male inflorescence> leaf> female inflorescence> fine root;and then the average zinc content of each organ was: exocarp> species> leaf> fruit shell> fine roots.The results showed that the pecan was a kind of high-zinc-resistant plant,and the nutrient solution of 6.12 ?mol/L Zn had better growth of pecan seedling.The zinc concentration of stem and leaf reached the maximum at 36.25 ?mol/L Zn,which was 510.54 mg/kg and 439.77 mg/kg,respectively.Seedling died of zinc poisoning at 906.25 ?mol / L zinc.The response of different organs to Zn stress was different,and roots were more sensitive to Zn.In the stem and leaf,there is synergistic effect between K,Mg and Zn.The results showed that low zinc inhibited the growth of grafted seedlings of hatchback.The zinc concentration in the zinc-free treatment group was 133.91 mg/kg,which was 79.71% of that of 6.12 ?mol/L zinc treatment.The maximum net photosynthetic rate was 2.77 ?mol/(m2·s),which was 23% of that of 6.12 ?mol/L zinc treatment.Under the condition of low zinc,the zinc in the roots is transferred to the aerial part,the root accumulation is relatively small,and the zinc in the stem and branch is preferentially satisfied.The values of light saturation point,light compensation point and maximum net photosynthetic rate decrease with the decrease of zinc concentration.The results showed that the content of amino acids,oil and other organic matter in the nuts of 0.4%zinc sulfate(T1 treatment)was higher than that of 1.6% zinc sulfate(T2 treatment)and CK(control).The concentration of zinc in the outer skin was T2(218.71 mg/kg)> T1(107.95 mg/kg)> CK(87.20 mg/kg),and the concentration of zinc in the kernel was T2(131.80 mg/kg)> T1(87.59 mg/kg)> CK(75.88 mg/kg).Appropriate amount of zinc can improve the fruit quality of pecan.