4个品种核桃砧木幼苗干旱生理响应及抗旱性评价

【目的】对4个品种核桃砧木幼苗进行抗旱性评价,旨在筛选适合干旱、半干旱核桃产区的优良抗旱核桃砧木。【方法】以4个常用核桃砧木品种为试材,研究干旱对其盆栽幼苗生长速率、水分利用效率、光合参数和叶绿素荧光参数的影响,采用模糊数学隶属函数法对其抗旱性进行综合评价。【结果】干旱条件下,核桃砧木幼苗间存在显著的品种间差异,其中,‘鸡爪绵’的相对生长速率(R)、长期水分利用效率(R_LWUE)、净光合速率(P_n)和光系统Ⅱ的最大光化学效率(F_v/F_m)最高,分别为0.92 mg/d、70.24 g/L、15.22 μmol/(m²·s)和0.79。干旱显著降低了核桃砧木幼苗的R、P_n和F_v/F_m,其中‘鸡爪绵’的降低幅度最小,分别为30.30%、22.78%和7.06%。干旱显著提高了核桃砧木幼苗的R_LWUE和瞬时水分利用效率(R_IWUE)。‘核桃楸’的R_LWUE

Physiological responses to drought stress and resistances evaluation of four cultivars of walnut rootstock seedlings

【Objective】Resistances to drought stress of four cultivars of walnut rootstock seedlings were evaluated,in order to screen out some fine drought-resistant walnut rootstock that can be applied in arid and semi-arid regions.【Method】Four commonly cultivars of walnut rootstocks were selected as test materials,influences of drought stress on relative growth rate,water use efficiency,photosynthesis parameters and chlorophyll fluorescence parameters in potted seedlings were researched.Drought resistances were comprehensively evaluated by using subordinate function method in fuzzy mathematics.【Result】There are significant differences among four cultivars of walnut rootstock seedlings under drought condition.‘Jizhuamian’had the highest values of relative growth rate(R),long-term water use efficiency(RLWUE),net photosynthetic rate(Pn),and maximum photochemical efficiency of PSⅡ(Fv/Fm),and they are 0.92 mg/d,70.24 g/L,15.22μmol/(m2·s)and 0.79,respectively.Drought stress significantly reduces R,Pn and Fv/Fm in walnut rootstock seedlings.‘Jizhaomian’shows the smallest decrease of R(30.30%),Pn(22.78%)and Fv/Fm(7.06%).Meanwhile,RLWUE and instantaneous water use efficiency(RIWUE)are significantly enhanced by drought stress.‘Hetaoqiu’shows the highest increase of RLWUE(16.20%),followed by‘Jizhuamian’(15.70%).‘Jizhuamian’shows the highest increase of RIWUE(16.61%).Average subordinate function values of‘Jizhuamian’‘Xiangling’‘Hetaoqiu’and‘Black walnut’are 0.99,0.68,0.48 and 0.07,respectively.So drought resistance has large variation among four cultivars of walnut rootstock seedlings.【Conclusion】‘Jizhuamian’and‘Xiangling’show higher drought tolerances,their seeds are easy to be collected,so they are suitable for application in arid and semi-arid regions.‘Black walnut’and‘Hetaoqiu’are not suitable for application in arid regions due to weak drought resistance and difficulty of seed collection.