摘要
为探明外源褪黑素(MT)延缓厚皮甜瓜叶片衰老的生理机制及其对果实品质的影响,本研究以‘农大103’厚皮甜瓜为材料。春季大棚栽培条件下于雌花开放期叶面喷施100、200、300、400μmol/L MT溶液(以喷施蒸馏水为对照),系统分析坐果节位叶片的叶绿素含量、叶绿素荧光参数、光合参数、抗氧化系统(酶活性、抗氧化物质、活性氧)及氮代谢关键酶(硝酸还原酶NR、谷氨酰胺合成酶GS)活性,并测定果实品质指标。结果表明:与对照相比,各MT处理均显著提高叶片叶绿素含量、叶绿素荧光参数(如电子传递速率ETR)、净光合速率(Pn)、抗氧化酶(如抗坏血酸过氧化物酶APX、谷胱甘肽还原酶GR)活性及抗氧化物质含量,降低活性氧积累,增强NR和GS活性,同时提升果实单果重、维生素C(Vc)和可溶性糖含量。其中,200μmol/L MT处理效果最为显著。在喷施后14~35 d内,该处理使叶绿素含量、ETR、Pn分别平均提高58.59%、42.39%和82.38%;APX、GR和NR活性分别平均提高32.33%、34.73%和39.40%;果实可溶性固形物和Vc含量分别提高45.17%和66.24%。表明,外源MT可通过增强抗氧化能力以减轻氧化损伤、延缓叶片衰老,并通过提升光合效能和促进氮代谢,最终提高厚皮甜瓜果实产量和品质。本试验条件下,200μmol/L MT为延缓叶片早衰并优化果实品质的最适浓度。
To explore the physiological mechanism of exogenous melatonin(MT)in delaying the senescence of thickskinned melon leaves and its effect on fruit quality,this study used'Nongda 103'thickskinned melon as the material.Under spring greenhouse cultivation conditions,100,200,300,and 400µmol/L MT solutions were sprayed on the leaves at the time of female flower opening(with distilled water spraying as the control).The chlorophyll content,chlorophyll fluorescence parameters,photosynthetic parameters,antioxidant system(enzyme activity antioxidant substances,reactive oxygen species),and activities of key enzymes in nitrogen metabolism(nitrate reductase NR and glutamine synthetase GS)of the leaves at the fruiting node were systematically analyzed,and the fruit quality indicators were measured.The results showed that compared with the control,all MT treatments significantly increased the chlorophyll content,chlorophyll fluorescence parameters(such as electron transfer rate ETR),net photosynthetic rate(Pn),activities of antioxidant enzymes(such as ascorbate peroxidase APX and glutathione reductase GR),and contents of antioxidant substances,reduced the accumulation of reactive oxygen species,enhanced the activities of NR and GS,and simultaneously increased the fruit weight,vitamin C(Vc),and soluble sugar content.Among them,the 200µmol/L MT treatment was the most significant.Within 14 to 35 days after spraying,this treatment increased the chlorophyll content,ETR,and Pn by an average of 58.59%,42.39%,and 82.38%,respectively;increased the activities of APX,GR,and NR by an average of 32.33%,34.73%,and 39.40%,respectively;and increased the soluble solids and Vc content of the fruit by 45.17%and 66.24%,respectively.It indicated that exogenous MT can delay leaf senescence by enhancing antioxidant capacity to reduce oxidative damage and improve photosynthetic efficiency and promote nitrogen metabolism,ultimately increasing the yield and quality of thick-skinned melon fruits.Under the conditions of this experiment,200µmol/L MT is the optimal concentration for delaying leaf senescence and optimizing fruit quality.
作者
郑海强
刘梦泽
刘海河
张彦萍
曹艳霞
朱立保
ZHENG Haiqiang;LIU Mengze;LIU Haihe;ZHANG Yanping;CAO Yanxia;ZHU Libao(College of Horticulture,Hebei Agricultural University,Baoding 071001,China)
出处
《河北农业大学学报》
北大核心
2025年第6期54-62,共9页
Journal of Hebei Agricultural University
基金
国家西甜瓜产业技术体系资助项目(CARS-26-25)
河北省现代种业科技创新专项资助项目(21326306D)
河北省农业科技成果转化资金专项资助项目(冀科农函[2024]1号)。
关键词
厚皮甜瓜
褪黑素
抗氧化酶
活性氧
氮代谢
果实品质
Muskmelon
Melatonin
Antioxidant enzymes
Reactive oxygen species
Nitrogen metabolism
Fruit quality
