Effect Of MnSO₄on Photosynthetic Characteristics And Mineral Nutrition In ’Shi-men-zao-shuo’ Chestnut Tree

Mn is a component more important in chestnut tree than other fruit trees. It is influenceon the photosynthesis and absorption and utilization of mineral nutrition in chestnut.Thedifferent ‘Shi-men-zao-shuo’(SMZS) plants were used as materials in the experiment. Theeffect of MnSO4on photosynthetic characteristics of chestnut and the nutrition were studiedby potting or field, applying manganese fertilizer to soil or foliar spray. The main results wereas followed:1Daily variation of photosynthetic rate of the SMZS chestnut presented a single peakcurve during late June and early July. The diurnal variation of Pn, Tr and Gs were improvedobviously by spraying continuously0.3%FeSO4, but there were no significant differences inTr and Gs by spraying0.3%MnSO4. It has increased the photosynthesis in chestnut at13:00and elongated the effective photosynthetic time by spraying0.3%MnSO4and FeSO4.2It can improve photosynthesis effectively by supplying proper quantity of MnSO4before defoliation in autumn. And the increase amplitude for Pn was31.4%. Photosynthesiswas inhibited by supplying excess manganese. The photosynthetic rate of chestnut leaves wasimproved effectively for supplying with proper quantity of MnSO4to soil in spring, and theamplification of Pn was31.03%.3The annual variation of Pn of SMZS presented bimodal curve, and the peaks wereshowed respectively in the flowering stage at the beginning of May and the fruit expandingperiod in late August. The biosynthesis of chlorophyll and Pn were improved by supplyingwith proper concentration MnSO4.The amplification of Pn and relative Chlorophyll content(SPAD value) were12.20%and9.61%by supplying130g MnSO4per chestnut plant.4It could promote the absorption of manganese nutrition and adjust the transport andutilization within the chestnut, with and increase of manganese concentration in soil. Thecontent of N, P, Mg, Ca, Fe and Mn in the leaves, branch and root of chestnut showed that thecontent of N in strong branch was higher than in weak branch, and the content of othermineral nutrition in weak branch was higher than in strong branch; the content of N, P, Ca,Mg, Mn and Fe in weak leaf was higher than that in strong leaf. The contents of N, P, Mg andMn in root, branch and leaf were improved by supplying proper concentration of MnSO4, butthe content of Ca and Fe was restrained. 5There were the parabola types for the Chl content, Pn, Gs and Tr when the contents ofMnSO4in soil were in the range of0～120g/plant, and the peak of Tr was presented at thelevel of60g/plant, others were presented at the level of120g/plant by the treatment methodsof storing water and fertilizer in the hollow. Ci reduced first then raised and reduced againwith the increasing of manganese content in the third month, and the low ebb was presented atthe level of60g/plant when the peak was presented at the level of120g/plant; Ci increased atfirst and then decreased with the increase of manganese content in the sixth month, and thelow ebb was presented at the level of30g/plant. Photosynthetic efficiency increasedeffectively by soil application MnSO4(0～120g), and the effect of storing water and fertilizerin the hollow was better than surface fertilization.6The yields of the chestnut plant can be increased by applying MnSO4(0～130g/plant)in soil, but there was not significant differences.