外源茉莉酸甲酯对镉胁迫马铃薯光合荧光特性及块茎产量的影响

Effects of exogenous MeJA on photosynthetic physiology,chlorophyll fluorescence characteristics and tuber yield of potato under cadmium stress

【目的】探明外源茉莉酸甲酯(MeJA)对镉胁迫马铃薯光合生理特性及块茎产量的影响。【方法】采用盆栽试验,以200μmol/L CdCl2胁迫下的马铃薯品种大西洋为试验材料,共设不喷施MeJA(CK)、喷施0.1μmol/L MeJA(T1)、喷施1μmol/L MeJA(T2)、喷施10μmol/L MeJA(T3)4个处理,分别于苗期、开花期、薯块膨大期和成熟期取样,分析MeJA对镉胁迫马铃薯叶片叶绿素(叶绿素a(Chla)、叶绿素b(Chlb)、叶绿素a+b(Chl(a+b))含量、光合指标(净光合速率(P_(n))、气孔导度(G_(s))、蒸腾速率(T_(r))、胞间CO_(2)浓度(C_(i)))、叶绿素荧光参数(初始荧光(F_(0))、最大荧光产量(F_(m))、可变荧光(F_(v))、PSⅡ最大光化学量子产量(F_(v)/F_(m)))、块茎产量及其镉含量的影响,并分析了马铃薯叶片叶绿素含量、光合指标、叶绿素荧光参数与产量的相关性。【结果】在马铃薯苗期、开花期、薯块膨大期和成熟期,与CK相比,喷施MeJA均可以提高镉胁迫马铃薯叶片的叶绿素含量及P_(n)、G_(s)、T_(r)、F_(0)、F_(m)、F_(v)和F_(v)/F_(m),降低Ci。在同一时期的4个MeJA处理中,T_(2)处理马铃薯叶片的叶绿素含量、P_n、G_(s)、T_(r)、F_(0)、F_(m)、F_(v)、F_(v)/F_(m)总体最高,C_(i)最小。喷施不同浓度MeJA对镉胁迫马铃薯块茎产量和及其镉含量有明显影响,与CK相比,T_(1)、T_(2)、T_(3)处理马铃薯的块茎产量显著增加了21.14%,34.60%和16.91%,块茎镉含量显著下降了48.09%,57.02%和38.70%。相关性分析表明,马铃薯产量与Chla、Chlb、Chl(a+b)、P_(n)、T_(r)呈显著正相关。【结论】外源MeJA能够改善镉胁迫马铃薯叶片的光合作用,提高块茎产量,其中以1μmol/L MeJA处理效果最优,可有效缓解镉胁迫对马铃薯造成的不利影响。

【Objective】This study investigated the effects of exogenous methyl jasmonate(MeJA)on photosynthetic physiological characteristics and tuber yield of potato under cadmium stress.【Method】‘Atlantic’potato under 200μmol/L CdCl_(2) stress was planted in pots with four treatments of spraying 0(CK),0.1(T1),1(T2)and 10μmol/L MeJA(T3).Samples were collected at seedling,flowering,potato swelling and ripening stages to analyze MeJA leaf chlorophyll indexes(chlorophyll a(Chla),chlorophyll b(Chlb)and chlorophyll a+b(Chl(a+b)),photosynthetic indexes(net photosynthetic rate(P_(n)),stomatal conductance(G_(s)),transpiration rate(T_(r))and intercellular CO_(2) concentration(C_(i))and chlorophyll fluorescence parameters(initial fluorescence(F_(0)),dark adapted maximum fluorescence(F_(m)),variable fluorescence(F_(v))and MAS maximum photochemical quantum yield of PSⅡ(F_(v)/F_(m)))of cadmium stress potato,as well as tuber yield and its cadmium content.The correlations of chlorophyll contents,photosynthetic indexes,chlorophyll fluorescence parameters and yield were also analyzed.【Result】At seedling,flowering,tuber expansion and maturity stages,MeJA increased chlorophyll contents,P_(n),G_(s),T_(r),F_(0),F_(m),F_(v) and F_(v)/F_(m),while reduced C_(i) in Cd-stressed potato leaves compared to CK.T_(2) had the highest values of chlorophyll contents,P_(n),G_(s),T_(r),F_(0),F_(m),F_(v) and F_(v)/F_(m) and the lowest C_(i) value.MeJA spraying had significant effects on yields of Cd-stressed potato tubers and their Cd contents.Compared with CK,tuber yields of T_(1),T_(2) and T_(3) treatments were significantly increased by 21.14%,34.60%and 16.91%,and tuber Cd contents were significantly decreased by 48.09%,57.02%and 38.70%,respectively.Correlation analysis showed that tuber yield was significantly and positively correlated with Chla,Chlb,Chl(a+b),P_(n) and T_(r).【Conclusion】Exogenous MeJA improved photosynthesis in potato leaves under Cd stress and increased tuber yield,and the 1μmol/L MeJA treatment was the most effective in alleviating adverse effects of Cd stress.