摘要
【目的】探究水氮互作对石榴幼苗光合荧光及生理特性的影响。【方法】采用盆栽控水法,设置3个灌水(W1:灌水上下限为田间持水量的35%~45%;W2:灌水上下限为田间持水量的55%~65%;W3:灌水上下限为田间持水量的75%~85%)与4个施氮耦合(N0,0 g·kg^(-1);N1,0.1 g·kg^(-1);N2,0.2 g·kg^(-1);N3,0.3 g·kg^(-1))处理,探索不同处理对叶片叶绿素含量、光合荧光特性、渗透调节物质含量与氮代谢酶活性的影响。【结果】叶绿素含量、光合特性(P_(n)、G_(s)、T_(r))、叶绿素荧光参数(除NPQ外)、氮代谢酶活性均在W2条件下最佳;且随灌水量降低,可溶性蛋白(SP)含量降低,可溶性糖(SS)与脯氨酸(Pro)含量升高。W3条件下,除G_(S)活性以N2处理最佳外,叶绿素含量、光合特性、荧光参数[F_(v)/F_(m)、ETR、Y(Ⅱ)]、渗透调节物质含量与其余氮代谢酶活性均随施氮量的增加而提高;W2条件下,叶绿素含量、光合特性、荧光(除NPQ外)、SP含量及氮代谢酶活性在整个处理过程中均以N2处理最高,SS和Pro含量随施氮量的增加而增加;W1条件下,叶绿素含量、光合特性(P_(n)、G_(s)、T_(r))、荧光(除NPQ外)、SP、SS含量和氮代谢酶活性随氮肥的增加而减少,Pro含量变化与之相反,且在各灌水条件下,NPQ变化与F_(v)/F_(m)相反,C_(i)与NPQ变化呈负相关。【结论】综合各项指标发现,通过合理施用氮肥可有效缓解干旱胁迫,W2N2为该试验条件下的最佳水氮组合。
【Objective】This experiment aimed to investigate the interaction of water and nitrogen on photosynthetic fluorescence and physiological characteristics of the soft seed pomegranate(Punica granatum L.)seedlings under water shortage in Shihezi,Xinjiang in order to offer a clue for saving water and determine the optimal combination of water and nitrogen.Tunisia soft seed pomegranate seedlings were used as the test materials.The effects of different water and nitrogen treatments on the photosynthetic characteristics and chlorophyll fluorescence of the leaves of the seedlings were investigated,and the osmotic regulation ability of the seedlings and their effects on nitrogen metabolism were also studied.【Methods】The pot water control method was used to set three irrigation levels(W1:35%-45%of the field water capacity,W2:55%-65%of the field water capacity,W3:75%-85%of the field water capacity)and four nitrogen application levels(N0:0 g·kg^(-1) soil,N1:0.1 g·kg^(-1) soil,N2:0.2 g·kg^(-1) soil,N3:0.3 g·kg^(-1) soil),respectively.The chlorophyll content,photosynthesis and chlorophyll fluorescence characteristics of the seedlings were measured on the 40th day,and osmotic regulation substance content and key enzyme activities of nitrogen metabolism were measured on the 10th,20th,30th and 40th days after water-nitrogen interaction treatments.【Results】In terms of the photosynthetic characteristics and chlorophyll fluorescence,the chlorophyll content,net photosynthetic rate(P_(n)),stomatal conduc-tance(G_(s)),transpiration rate(T_(r)),photochemical quantum efficiency(F_(v)/F_(m)),photochemical quenching coefficient(qP),photosynthetic electron transfer rate(ETR)and effective quantum yield[Y(Ⅱ)]of photochemical energy conversion in the leaves of the soft seed pomegranate seedlings achieved the optimal results under the W2 irrigation condition.Under various irrigation conditions,the increase of the nitrogen application rate could significantly increase the chlorophyll content and net photosynthetic rate,stomatal conductance and transpiration rate values,while intercellular CO_(2) concentration(C_(i))was negatively correlated with the net photosynthetic rate change under W1 irrigation condition,but positively correlated with the net photosynthetic rate change under the W2 and W3 irrigation condition.The variation trend of the non-photochemical quenching coefficient(NPQ)was opposite to that of the photochemical quantum efficiency.In terms of osmotic regulation and nitrogen metabolism,the contents of soluble protein and soluble sugar and proline in the leaves of the seedlings decreased with the decrease of the irrigation amount.The nitrate reductase(NR),glutamine synthetase(GS),glutamic oxaloacetate transaminase(GOT)and glutamic pyruvate transaminase(GPT)achieved the highest activities under the W2 irrigation condition.Except that the glutamine synthetase activity treated with N2(0.2 g·kg^(-1) soil)reached the optimal results,the contents of soluble protein,soluble sugar and proline and the activities of nitrate reductase,glutamic oxaloacetate transaminase and glutamic pyruvate transaminase increased with the increase of nitrogen application level under the W3 irrigation condition(the upper and lower limits of irrigation were 75%to 85%of the field water capacity).Under the condition of the W2(the upper and lower limits of irrigation were 55%-65%of the field water capacity),the soluble protein content and the activities of key enzymes of the nitrogen metabolism reached the highest levels in the N2 treatment,and the contents of soluble sugar and proline increased with the increase of nitrogen application rate.Under the W1 irrigation(the upper and lower limits of irrigation were 35%-45%of the field water capacity),the contents of soluble protein and soluble sugar decreased with the increase of nitrogen application rate,while the proline content remained an opposite alteration.The activity of nitrogen metabolism enzymes was the highest in the N1 treatment,followed by the N2,N3 and N0 treatments.【Conclusion】The photosynthetic fluorescence characteristics of the soft seeds pomegranate seedlings could be inhibited by drought to a certain extent.The drought stress could be effectively alleviated by the osmotic regulation ability,key enzyme activity,and nitrogen metabolism through the appropriate increase of nitrogen application.In addition,W2N2 seems to be the best combination of water and nitrogen in this study.The results could provide a theoretical basis for raising the soft seed pomegranate seedlings in Shihezi,Xinjiang to a certain extent.
作者
柴亚倩
关思慧
崔洪鑫
许静
朱晓玲
刁明
孔秋生
CHAI Yaqian;GUAN Sihui;CUI Hongxin;XU Jing;ZHU Xiaoling;DIAO Ming;KONG Qiusheng(School of Agriculture,Shihezi University/Key Laboratory of Special Fruit and Vegetable Cultivation,Physiology and Germplasm Re�sources Utilization,Xinjiang Production and Construction Group,Shihezi 832003,Xinjiang,China)
出处
《果树学报》
CAS
CSCD
北大核心
2022年第12期2352-2364,共13页
Journal of Fruit Science
基金
兵团科技攻关重点项目(2021AB015)。
关键词
石榴幼苗
水氮
光合
渗透调节
氮代谢
Pomegranate seedlings
Water and nitrogen
Photosynthesis
Osmoregulation
Nitrogen metabolism
