北高丛蓝莓品种耐较高土壤pH值胁迫能力综合评价和指标筛选

Comprehensive valuation and indicators of the tolerance to higher soil pH stress of 11 northern highbush blueberry varieties

【目的】研究较高土壤pH值胁迫对北高丛蓝莓幼苗生长和生理特性的影响,筛选出耐较高土壤pH值胁迫能力强的品种和评价指标,为蓝莓抗性育种和合理栽培提供理论依据和技术支持。【方法】以11个北高丛蓝莓品种一年生扦插苗为试材,测定对照(pH为5.0)和较高土壤pH值(pH为6.0)处理下生长和生理指标的变化情况,评价不同品种耐较高土壤pH值能力,并筛选关键的鉴定指标。【结果】与对照相比,在具较高土壤pH值胁迫条件下,参试品种丙二醛(MDA)含量、过氧化氢酶(CAT)活性基本上显著升高,胞间CO2浓度(Ci)基本保持稳定,而叶绿素(Chl)含量和最大光化学效率(Fv/Fm)均显著降低;多数蓝莓品种株高相对生长量、光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)、电子传递速率(ETR)和光化学猝灭系数(qP)显著降低;耐较高土壤pH值胁迫能力强的品种非光化学猝灭系数(NPQ)明显升高。【结论】11个北高丛蓝莓品种中‘双迪’‘甜心’‘伊丽莎白’‘埃利奥特’‘钱德勒’耐较高土壤pH值胁迫能力较强。Tr、Gs、株高相对生长量、ETR、CAT活性和叶绿素含量可作为鉴定北高丛蓝莓品种耐较高土壤pH值胁迫能力的关键指标。

【Objective】In this study,we investigated the effects of higher soil pH stress on the growth and the physiological characteristics of northern highbush blueberry(Vaccinium Spp.)cutting seedlings of 11 varieties,to screen the varieties with strong tolerance to higher soil pH stress and the indicators of the tolerance to provide a theoretical basis and technical support for breeding new variety with resistance to higher pH and rational cultivation of blueberries.【Methods】Changes of the relative height growth,malonaldehyde(MDA)content,superoxide dismutase(SOD)activity,peroxidase(POD)activity,catalase(CAT)activity,Chlorophyll content,gas exchange parameters,and chlorophyll fluorescence parameters of Eleven Northern highbush blueberries(including‘Bluecrop’‘Reka’‘D-ⅡMSU54’‘Spartan’‘Cara’s Choice’‘Elizabeth’‘Chandler’‘Brigitta’‘Duke’‘Sweetheart’and‘Elliott’)were determined to evaluate the tolerance of different blueberry varieties to the higher soil pH stress,and to select the indicators of the tolerance,using their one-year-old cutting seedlings under the higher soil pH(6.0)treatment and the control(pH 5.0).【Results】The relative growth of height of the cutting seedlings of‘D-ⅡMSU54’and‘Elizabeth’treated with higher pH was not significantly lower than that of the seedlings of the control,the relative growth of height of the seedlings under higher soil pH stress of the other varieties were significantly lower than those of the seedlings of the control.‘D-ⅡMSU54’and‘Sweetheart’were mildly injured with an injury index of 2.00%and 6.67%respectively;‘Spartan’and‘Duke’were seriously injured with an injury index of 73.33%and 53.33%respectively;the damage degree of the other varieties sat in the mid under the higher soil pH stress.Compared with the control,the MDA content and CAT activity of all tested varieties significantly increased,intercellular carbon dioxide(Ci)mainly kept stable,the chlorophyll(Chl)content and maximal quantum efficiency of photosystemⅡ(Fv/Fm)significantly decreased.In addition,net photosynthetic rate(Pn),transpiration rate(Tr),stomatal conductance(Gs),electron transport rate(ETR)and photochemical quenching coefficient(qp)of the majority of the blueberry varieties were significantly decreased,the non-photochemical quenching coefficient(NPQ)of the varieties with strong tolerance to the higher soil pH stress significantly increased under higher soil pH stress for 90 days.The principal component analysis showed that the relative values of those indices were classified into two independent comprehensive indices(principal component).The principal component 1 mainly reflected the information of the plant height growth characteristics,the CAT activity,the main leaf physiological characteristics and the fluorescence parameters;the principal component 2 mainly reflected the information of the SOD activity.Comprehensive evaluation of the higher soil pH stress-tolerance(D value)showed that the ability of tolerance to the higher soil pH stress decreased in order of‘D-ⅡMSU54’>‘Sweetheart’>‘Elizabeth’>‘Elliott’>‘Chandler’>‘Bluecrop’>Reka’>‘Cara’s Choice’>‘Brigitta’>‘Duke’>‘Spartan’.Eleven blueberry varieties were divided into three categories by clustering analysis:the higher soil pH tolerant type,the middle type,and the higher soil pH intolerant type.The correlation degree between the relative values of fifteen indexes and the D value decreased in order of Tr>Gs>height relative growth>ETR>CAT activity>Chl content>qP>Pn>NPQ>POD activity>SOD activity>Ci>Fv/Fm>MDA content by grey correlation analysis.【Conclusion】The higher soil pH stress had significant influence on each index during growth stage of the cutting seedings of blueberry.Compared with the blueberry variety with intolerance to the higher soil pH stress,the CAT activity of the tolerant varieties maintained a in a relatively high level,the photosynthetic structure was slightly damaged,the photosynthesis was less affected,as a result,the high relative growth was less affected and the damage was less.Eleven Northern highbush varieties were divided into three categories by clustering analysis:the higher soil pH stress-tolerant type(including‘D-ⅡMSU54’‘Sweetheart’‘Elizabeth’‘Elliott’‘Chandler’),the intermediate type(including‘Bluecrop’‘Reka’and‘Cara’s Choice’)and the higher soil pH stress-intolerant type(including‘Brigitta’‘Duke’and‘Spartan’).Among the fourteen higher soil pH tolerance related indexes of the Northern highbush blueberry under higher soil pH stress,Tr,Gs,the relative growth of height,the ETR,the CAT activity and the Chl content could be used as key indexes to identify the tolerance of the Northern highbush blueberry to the higher soil pH.