不同外源糖对根区亚低温下山定子生长和养分吸收的影响

Effect of different exogenous sugars on the growth and nutrient uptake of Malus baccata Borkh.under sub-low root zone temperature

我国北方春季土温回升慢,常使苹果根系遭受亚低温胁迫。糖在根系响应低温胁迫过程中充当着营养成分和信号分子的双重功能。为探究不同外源糖对根区亚低温下山定子生长和养分吸收的影响,本试验设置对照(CK)、根区亚低温(L)、根区亚低温+蔗糖(LS)、根区亚低温+果糖(LF)和根区亚低温+葡萄糖(LG)5个处理,分析了山定子幼苗生长参数、叶片光合特性和不同组织矿质元素含量。结果表明:与CK相比,L处理后山定子株高、根系生长参数、地上部生物量、叶片光合和荧光参数及叶绿素含量均显著降低;除根系钙(Ca)含量显著升高外,山定子幼苗中的氮(N)、磷(P)、钾(K)、钙(Ca)和镁(Mg)含量均显著降低。与L处理相比,外源蔗糖、果糖和葡萄糖处理后,山定子叶片光合和荧光参数、叶绿素含量、生长参数均不同程度升高;根中N和P含量显著增加;茎中N、P和K含量显著增加,茎中Ca含量只在蔗糖处理后显著增加;叶中N、P、K、Ca和Mg含量均显著增加。综上,根区亚低温下外源糖处理可提高山定子叶片光合效率,促进矿质元素吸收,进而缓解根区亚低温对植株生长发育的抑制,且蔗糖处理效果好于果糖和葡萄糖处理。

In northern China,soil temperature slowly rises in spring,often subjecting apple roots to sub-low-temperature stress.Sugar acts as both a nutrient and signaling molecule in roots in response to low-temperature stress.To explore the effects of exogenous sugars on the growth and nutrient absorption of Malus baccata Borkh.,we analyzed growth parameters,photosynthetic characteristics of leaves,and mineral element content in different tissues of M.baccata seedlings under five treatments,including control(CK),sub-low root zone temperature(L),sub-low root zone temperature+sucrose(LS),sub-low root zone temperature+fructose(LF),and sub-low root zone temperature+glucose(LG).The results showed that compared to CK,plant height,root growth parameters,aboveground biomass,leaf photosynthesis,fluorescence parameters,chlorophyll content,and the contents of nitrogen(N),phosphorus(P),potassium(K),calcium(Ca)and magnesium(Mg)in M.baccata seedlings were significantly decreased under the L treatment,and the content of Ca in roots was significantly increased.Compared to the L treatment without exogenous sugar,photosynthesis,functional parameters,chlorophyll content,and growth parameters increased to different degrees after exogenous sucrose,fructose,and glucose application.The N and P contents in roots were significantly increased.The N,P,and K contents significantly increased in stems while only the Ca content significantly increased in stems treated with sucrose.Leaf N,P,K,Ca,and Mg contents significantly increased after being treated with the three exogenous sugars.In conclusion,exogenous sugars can improve photosynthetic efficiency,promote mineral element absorption,and alleviate the inhibition of growth and development of M.baccata at sub-low root zone temperatures,and the effect of sucrose treatment was better than that of fructose and glucose treatments.