干旱胁迫对苹果树生长、光合特性及果实品质的影响

Effects of drought on growth,photosynthetic characteristics and fruit quality of apple trees

阐明极端干旱区成龄苹果树干旱胁迫后的生理响应可以为其科学灌溉提供理论依据.以塔里木盆地周边绿洲的成龄苹果树为研究对象,在蒸发量最大的6—8月(果实膨大期)开展干旱胁迫试验,设置干旱处理(T1,灌溉1次、灌溉量1500 m^(3)/(hm^(2)·次)),对照(CK,灌溉2次、灌溉量1500 m^(3)/(hm^(2)·次)),分析4种枝条(结果短枝、结果长枝、果苔枝、生长枝)在受到干旱胁迫后的生长生理特性变化规律以及果实产量品质的影响.结果表明,干旱胁迫处理(T1)的生长枝在8月9日停长,较CK(8月19日停长)提前10 d,T1的生长枝长度(63 cm)较CK处理(122 cm)减少48.36%;T1处理果实的纵横经稍低于CK,但未达到显著性差异(P>0.05).干旱胁迫60 d后,4种枝条的日均P_(n)极显著低于对照(P<0.01),结果短枝、结果长枝、果苔枝、生长枝分别下降53.00%、57.00%、54.49%、62.21%;日均Gs也极显著低于对照(P<0.01),结果短枝、结果长枝、果苔枝、生长枝分别下降53.85%、62.50%、58.21%、60.81%.随着干旱胁迫的加剧,P_(n)值越来越小,非气孔因素占主导作用,光合机构受损伤程度越来越大.干旱胁迫后的单株产量显著低于对照(P<0.05),但反映果实品质的可溶性固形物、VC质量比、p H值均极显著高于对照(P<0.01),总酸质量比显著低于对照(P<0.05).苹果园管理在果实膨大期之后开始合理控水,有助于果树从营养生长向生殖生长转化,且可以有效提高果实品质.

Elucidating the physiological response of adult apple trees under drought stress in extreme arid areas can provide a theoretical basis for scientific irrigation.Taking the mature apple trees in the oases around Tarim Basin as the research object,the drought stress test was carried out from June to August(fruit expansion period)with the maximum evaporation.The drought treatment(T1,irrigation once,irrigation amount 1500 m^(3)/(hm^(2)·times))and the control(CK,irrigation twice,irrigation amount 1500 m^(3)/(hm^(2)·times))were set to analyze the changes of growth physiological characteristics and the effects of fruit yield and quality of four branches(short fruiting branch,long fruiting branch,moss fruiting branch and growing branch)under drought stress.The results showed that the growth branches of drought stress treatment(T1)stopped growing on 9 th August,10 days earlier than CK(19 th August),and the growth branch length of T1(63 cm)decreased by 48.36%compared with CK(122 cm).The longitudinal and transverse meridians of T1 treatment were slightly lower than CK,but there was no significant difference(P>0.05).After 60 days of drought stress,the daily average P_(n)of the four branches was significantly lower than that of the control(P<0.01).The short fruiting branch,long fruiting branch,moss fruiting branch and growing branch decreased by 53.00%,57.00%,54.49%and 62.21%respectively.The daily average Gs was also significantly lower than that of the control(P<0.01).The short fruiting branch,long fruiting branch,moss fruiting branch and growing branch decreased by 53.85%,62.50%,58.21%and 60.81%respectively.With the aggravation of drought stress,P_(n)value is becoming smaller and smaller,non stomatal factors play a leading role,and the damage degree of photosynthetic mechanism is becoming greater and greater.The yield per plant after drought stress was significantly lower than that of the control(P<0.05),but the soluble solids,VC content and pH value reflecting fruit quality were significantly higher than that of the control(P<0.01),and the total acid content was significantly lower than that of the control(P<0.05).The reasonable water control of apple orchard management after the fruit expansion period is helpful to the transformation of fruit trees from vegetative growth to reproductive growth,and can effectively improve the fruit quality.