AQPs、NO调节水稻种子萌发过程淀粉降解的研究  

Regulation of Starch Degradation by AQPs and NO During the Ger-mination of Rice Seeds

作　　者：卢志霞 谭春林 陈惠萍[1] LU Zhixia;TAN Chunin;CHEN Huiping(College of Life Science,Hainan University,Haikou,Hainan 570228,China)

机构地区：[1]海南大学生命科学学院,海南海口570228

出　　处：《热带作物学报》2024年第5期955-963,共9页Chinese Journal of Tropical Crops

基　　金：国家自然科学基金项目(No.31960453)。

摘　　要：水稻(Oryza sativa L.)是一种重要的粮食作物,其种子的正常萌发关乎后期植株的生长及产量。种子萌发始于干种子对水分的吸收,止于胚轴伸长。细胞内部及细胞间的水分运输,受水通道蛋白(aquaporins, AQPs)高度选择性调节。禾谷类的种子富含淀粉,内源性赤霉素可诱导α-淀粉酶等水解酶在胚中合成,并将其分泌至淀粉性胚乳中降解淀粉为小分子物质,供种子萌发需要。研究表明,只有α-淀粉酶才能完成水稻种子淀粉的降解。一氧化氮(nitric oxide,NO)是一种信号分子,可形成各种活性氮物质,并参与解除种子休眠信号传导过程,NO供体可通过提高淀粉酶活性促进种子萌发。为探究AQPs、NO对水稻种子萌发的影响,本研究以博Ⅱ优767的水稻杂交种子为试验材料,采用NO合成抑制剂N-硝基-L-精氨酸甲酯[N(G)-nitro-L-arginine methyl ester, L-NAME]、钨酸钠(sodium tungstate, ST)与NO外源供体硝普钠(sodium nitroprusside, SNP)、AQPs活性抑制剂氯化汞(HgCl_(2))等对水稻种子进行处理,并借助表观分析和指标检测等手段确定水稻种子萌发过程中种子吸水能力、淀粉酶活性和淀粉降解速率等的变化。研究结果表明:经90 mg/L HgCl_(2)预处理的水稻种子,其吸水能力、淀粉酶活性和萌发率均下降,淀粉含量保持较高水平,胚根和胚芽的生长受到抑制;而NO外源供体SNP则可逆转HgCl_(2)的效应,且NO合成抑制剂L-NAME(15 mmol/L)和ST(80μmol/L)对水稻种子萌发的作用效应与HgCl_(2)的相似。结果表明,在水稻种子早期萌发阶段,AQPs可通过NO介导诱发种子吸收水分,激发淀粉酶,加速淀粉降解,从而促进种子的萌发。探究AQPs与NO在调节水稻种子萌发过程中的关系,对提高农作物产量奠定理论基础。Rice(Oryza sativa L.)is an important food crop,and the normal germination of rice seeds is related to the growth and yield of the plant in the later period.The germination begins with water absorption by dry seeds and ends with cotyl elongation.Water transport within and between cells is highly selectively regulated by aquaporins(AQPs).The seeds of cereal are rich in starch.And the endogenous gibberellin can induce the synthesis of hydrolase such asα-amylase in the embryo and secrete them into the starchy endosperm to degrade starch into small molecules for seed germination.Studies have shown that onlyα-amylase can complete the degradation of starch in rice seeds.Nitric oxide(NO)is a signaling molecule that forms a variety of active nitrogen substances.It also participated in the signaling process of seed dormancy removal.NO donor plays a role in seed germination by enhancing amylase activity.NO donor can promote seed germination by improving the activity of amylase.Rice hybrid seeds of‘BoⅡyou 767’were used as experimental materials to investigate the effects of aquaporins(AQPs)and nitric oxide(NO)on the germination of rice seeds.In this study,NO synthesis inhibitors N-(G)-nitro-L-arginine methyl ester(L-NAME)and sodium tungstate(ST),sodium nitroprusside(SNP),an exogenous donor of NO,and mercury chloride(HgCl_(2)),an activity inhibitor of AQPs,were used to treat rice seeds.The changes of water absorption capacity,amylase activity and starch degradation rate during germination of rice seeds were determined in virtue of apparent analysis and index detection.The results showed that the water absorption capacity,amylase activity and germination rate decreased in the rice seeds treated with 90 mg/L HgCl_(2),while the starch content remained high,and the growth of radicle and germ was inhibited.However,NO exogenous donor SNP could reverse the effect of HgCl_(2).And the effect of NO synthesis inhibitors L-NAME(15 mmol/L)and ST(80µmol/L)on the germination of rice seeds was similar to that of HgCl_(2).The results

关 键 词：AQPS NO Α-淀粉酶 种子萌发 种子吸胀 

分 类 号：S511[农业科学—作物学]