不同品系花椒幼苗抗旱性研究

A study on drought resistance of seedlings of different Zanthoxylum bungeanum strains

研究花椒幼苗对土壤干旱胁迫的适应性,比较不同品系之间的抗旱性差异,为花椒耐旱品系的确定与应用提供理论依据。以中国北方果实品质较好的循化花椒、凤县花椒、秦安花椒、涉县花椒、韩城花椒等不同品系花椒1年生幼苗为材料,采用盆栽试验方法,设计4个土壤水分梯度进行控水处理,土壤相对含水量分别为75%~80%(对照)、55%~60%(轻度胁迫)、40%~45%(中度胁迫)和30%~35%(重度胁迫)。2016年5—9月份,测定不同水分条件下不同品系花椒的蒸腾耗水量、生物量及抗旱生理指标。采用模糊数学隶属函数法进行不同品系的抗旱性综合评价。结果表明,干旱胁迫时花椒蒸腾耗水量降低,且不同品系之间差异显著(P<0.05)。在中度水分胁迫条件下,循化、凤县、秦安、涉县、韩城花椒5—9月份的蒸腾耗水量分别为1148.97、1001.78、923.08、792.92、951.06 g。随着干旱胁迫程度的增加,花椒生物量减小,根冠比增大,根系干重占总生物量的比重呈增大趋势,而叶片干重占生物量的比重呈下降趋势。在中度胁迫时,循化、凤县、秦安、涉县、韩城花椒叶干重分别较对照降低了42.9%、42.8%、40.1%、38.5%、30.5%,在重度胁迫时分别降低了61.1%、58.4%、52.7%、48.8%、45.6%。重度干旱条件下,循化、凤县、秦安、涉县、韩城品系的苗高生长量分别较对照减小了61.6%、67.5%、56.2%、55.8%、47.2%(P<0.05),地径生长量分别较对照减小了38.7%、44.2%、34.5%、32.4%、32.7%(P<0.05),水分利用效率分别较对照提高了24.8%、32.7%、44.8%、26.2%、36.4%(P<0.05)。在土壤水分不足时,不同品系之间除了POD活性(轻度胁迫)外,各项生理指标差异显著(P<0.05)。韩城花椒和秦安花椒在干旱条件下具有较大的根冠比,叶片相对含水率较高,可溶性蛋白含量、脯氨酸含量、SOD和POD活性显著增大,MDA含量及细胞膜透性增幅较小,具有较强的抗旱性特征。不同品系花椒幼苗具有比较稳定的抗旱性差异。花椒幼苗的抗旱性排序为陕西韩城>河北涉县>甘肃秦安>青海循化>陕西凤县。生长在高海拔地区的花椒,对土壤水分不足比较敏感,抗旱性较差。在中国北方半湿润和半干旱气候区,适宜栽植陕西韩城和河北涉县品系的花椒。

This study assessed the adaptability of Zanthoxylum bungeanum seedlings to drought stress and the difference between different strains including Xunhua(QHXH),Fengxian(SXFX),Qinan(GSQA),Shexian(HBSX),and Hancheng(SXHC)in China.A set of pot experiments was conducted to study water consumption,biomass,and the physiological characteristics of Z.bungeanum seedlings.The one-year-old seedlings of Xunhua(QHXH),Fengxian(SXFX),Qinan(GSQA),Shexian(HBSX),and Hancheng(SXHC)Z.bungeanum,which have better fruit quality in northern China,were used as materials.Four relative soil moisture contents were used including 75%~80%(suitable water,CK),55%~60%(mild stress,MIS),40%~45%(moderate stress,MOS)and 30%~35%(severe stress,SES)in the experiments.The water consumption,biomass,and drought resistance physiological indexes of different strains were measured in conditions of different moisture conditions from May to August,2016.The drought resistance of Z.bungeanum seedlings was comprehensively evaluated with the fuzzy mathematical membership function formula.The results showed that water consumption in Z.bungeanum decreased under drought stress,with significant differences(P<0.05)among strains.Under moderate drought conditions,water consumption of QHXH,SXFX,GSQA,HBSX,and SXHC from May to August were 1148.97 g,1001.78 g,923.08 g,792.92 g,and 951.06 g,respectively.Further increase in drought stress resulted in a reduction in total biomass,whereas the ratio of root dry weight to total biomass increased and that of leaf dry weight to total biomass decreased.Under moderate drought conditions,the leaf dry weight of QHXH,SXFX,GSQA,HBSX,and SXHC decreased by 42.9%,42.8%,40.1%,38.5%,and 30.5%,respectively.Under extreme drought conditions,these percentages decreased to 61.1%,58.4%,52.6%,48.9%,and 45.6%,respectively.Under severe water stress,the height and diameter growth of QHXH,SXFX,GSQA,HBSX,and SXHC decreased by 61.6%,67.5%,56.2%,55.8%,and 47.2%(P<0.05),and 38.7%,44.2%,34.5%,32.4%,and 32.7%(P<0.05),the WUE increased by 24.8%,32.7%,44.8%,26.2%and 36.4%(P<0.05),respectively,compared to the CK,and significant(P<0.05)changes in the physiological indexes were observed among different strains,except for POD(mild stress).Moreover,the content of soluble protein and proline,activity of superoxide dismutase and peroxidase,relative water content,water use efficiency of GSQA and SXHC significantly increased(P<0.05)with drought,which indicated stronger characteristics of drought resistance.Different strains showed relatively stable drought resistance.Drought resistance of different strains in decreasing order was as follow:SXHC>HBSX>GSQA>QHXH>SXFX,which were based on growth and physiological characteristics.The strains of SXHC and HBSX is thus more suitable for propagation in the semi-humid and semi-arid areas of northern China.Comprehensive evaluation of the drought resistance of Z.bungeanum was conducted by combining the physiological index and the growth index,which eliminated the one-sidedness of drought resistance evaluation when using a single physiological index.