【作者】 张俊杰；

【导师】 邵瑞鑫；

【作者基本信息】 河南农业大学 ， 作物学， 2023， 硕士

【摘要】 黄淮海地区作为我国重要的玉米主产区,水资源匮乏,且时空分布不均,降水量与作物需水量不匹配,这些因素使夏玉米在生长发育过程中经常受到干旱胁迫,导致玉米单产难以提升。为了探究不同程度干旱胁迫对夏玉米光合作用、抗氧化系统以及产量的影响,本试验于2020年至2021年进行池栽水分控制,根据多年夏玉米生长需水量估算花期前后的灌溉量,在14叶完全展开时开始控水,并每隔7 d进行灌溉,分3次灌溉,设置100%作物蒸散量（ET_C）（CK）、70%ET_C（WD1）、40%ET_C（WD2）和0 ET_C（WD3）等4个水分梯度。前期试验发现L-精氨酸可显著提高玉米苗期的抗旱性,为探究其不同施用方式的调控效果,本文通过盆栽试验,设置5个处理:正常水分处理（CK）、干旱处理（WD,田间持水量的50%±5%）、干旱+L-精氨酸拌种处理（DM）、干旱+L-精氨酸叶面喷施处理（DF）、干旱+L-精氨酸拌种+叶面喷施处理（DM+DF）。为了研究L-精氨酸最佳施用方式对田间产量的影响,本试验于2022年进行了池栽水分控制性实验,在14叶完全展开时到抽雄吐丝期干旱,设置4个处理,正常水分处理（CK）、应用L-精氨酸（MS+FA）、干旱处理（WD,田间持水量的50%±5%）、干旱并施用L-精氨酸（DM+DF）,测定叶片光合作用、抗氧化系统和产量等指标。具体结果如下:（1）不同程度干旱胁迫对夏玉米的光合性能产生了显著影响。具体表现为叶片叶绿素含量、光合性能综合指数(PI_ABS)和群体叶面积指数、光合势均低于对照组,光合同化物积累也受到一定程度的阻碍。此外,研究还发现,在干旱胁迫后,玉米叶片的抗氧化酶活性会升高,且干旱程度越深,抗氧化酶活性升高的幅度也越大。与CK相比,WD1、WD2、WD3处理使2020-2021年的穗粒数与CK相比分别降低3.10%、21.06%、25.28%,12.11%、27.35%、40.75%。WD1、WD2、WD3的百粒重与CK相比分别显著降低8.99%、9.66%、16.15%,18.86%、23.42%、30.65%。WD1、WD2、WD3的产量与CK相比分别显著降低34.34%、51.83%、53.56%,19.32%、45.79%、54.61%。（2）L-精氨酸的不同施用方式均能提高干旱条件下玉米叶片的叶绿素相对含量（SPAD）和光合性能综合指数(PI_ABS),同时也能显著提高玉米植株的叶面积指数、比叶重和生长速率。结果表明:DM、DF、DM+DF的绝对生长速率分别比WD提高59.65%、39.19%、106.09%,干旱15天的叶面积指数分别比WD显著提高486.87%、453.84%、943.45%。其中,拌种+喷施复合措施下,缓解干旱的效果更为显著。（3）采用350μmol L^-1的L-精氨酸以拌种加叶面喷施的方式显著提高干旱胁迫下玉米叶片中超氧化物歧化酶、过氧化物酶和过氧化氢酶的活性,降低了丙二醛含量和活性氧产生速率,同时增加了可溶性糖、可溶性蛋白的含量,从而增强了植株的抗逆性。另外,L-精氨酸的应用还能够增加叶片叶绿素含量,提高叶片光合作用的能力,延缓叶片衰老。此外,L-精氨酸的应用还能够增加玉米的穗长、行粒数、穗粒数,减少了秃尖长和败育率,提高了玉米的产量。应用L-精氨酸的处理使秃尖长和败育率比干旱条件下减少了22.59%和40.86%,穗粒数和产量分别增加了41.53%和13.89%。综上,不同程度干旱处理抑制了玉米叶片的光合作用,提高了细胞膜脂过氧化程度,引起细胞内部代谢紊乱。干旱处理下玉米穗粒数减少、籽粒重量下降,进而降低籽粒产量。而L-精氨酸处理后能够增加干旱条件下玉米植株的光合作用能力,改善植株水分代谢平衡,增强抗氧化系统,维持细胞膜的稳定性,从而增强玉米植株的抗旱性,提高产量。更多还原

【Abstract】 Huang-Huai-Hai area,as an important main corn producing area,is short of water resources,uneven distribution of time and space,and mismatch between precipitation and crop water requirement.These factors make summer corn often subject to drought stress during the growth and development process,which makes it difficult to increase the yield per unit area of corn.In order to explore the effects of different degrees of drought stress on photosynthesis,antioxidant system and yield of summer maize,water control was carried out in pool planting from 2020 to 2021.Irrigation before and after flowering was estimated according to the growth water requirement of summer maize for many years.Water control was started when the 14 th leaf was fully developed,and irrigation was conducted every 7 days,divided into three times.Set four water gradients: 100% Eapotranspiration ETC(CK),70% ETC(WD1),40% ETC(WD2),and 0 ETC(WD3).The preliminary experiment found that L-arginine could significantly improve the drought resistance of maize at seedling stage.In order to explore the regulation effect of different application methods,five treatments were set up through pot experiment: Normal water treatment(CK),drought treatment(WD,50% ± 5% of field capacity),drought + L-Arginine seed mixing treatment(DM),drought + L-Arginine foliar spraying treatment(DF),drought + L-Arginine seed mixing + foliar spraying treatment(DM + DF).In order to study the effect of optimal application of L-Arginine on field yield,this experiment conducted a water control experiment in pool planting in 2022.When 14 leaves were fully developed and dry at the stage of tasseling,four treatments were set: normal water treatment(CK),application of L-Arginine(MS + FA),drought treatment(WD,50% ± 5% of field water capacity),drought and L-Arginine(DM + DF)were applied to determine leaf photosynthesis,antioxidant system and yield.The specific results are as follows:(1)The photosynthetic performance of summer maize was significantly affected by drought stress.The results showed that drought stress had a significant effect on the photosynthetic performance of summer maize.The chlorophyll content,photosynthetic performance index(PIABS),leaf area index and photosynthetic potential of the leaves were lower than those of the control group,and the accumulation of photosynthetic assimilates was also hindered to some extent.In addition,the study also found that the antioxidant enzyme activity of maize leaves increased after drought stress,and the deeper the drought degree,the greater the increase of antioxidant enzyme activity.Compared with CK,WD1,WD2 and WD3 reduced the kernel number per ear in 2020-2021 by 3.10%,21.06%,25.28% and 12.11%,27.35%,40.75%,respectively.Compared with CK,the hundred seeds weight of WD1,WD2 and WD3 decreased by 8.99%,9.66%,16.15% and 18.86%,23.42%,30.65%,respectively.Compared with CK,the yield of WD1,WD2 and WD3 decreased significantly by 34.34%,51.83%,53.56% and 19.32%,45.79% 54.61%,respectively.(2)Different application modes of L-Arginine could increase the relative chlorophyll content(SPAD)and photosynthetic performance index(PIABS)of maize leaves under drought conditions,and also significantly increase the leaf area index,specific leaf weight and growth rate of maize plants.Among them,the effect of seed dressing + foliar spraying composite measures to alleviate drought is more significant.The data show that: The absolute growth rates of DM,DF and DM + DF were increased by 59.65%,39.19% and 106.09% compared with WD,respectively,respectively.Compared with WD,the leaf mass per area increased significantly by 91.40%,86.67% and 116.71%,respectively.The leaf area index during 15 days of drought increased significantly by 486.87%,453.84% and 943.45%,respectively.Among them,the effect of the combined measures of seed mixing and spraying was more significant.(3)The activities of superoxide dismutase,peroxidase and catalase in maize leaves under drought stress were significantly increased by using 350 μmol L-1 L-Arginine in seed dressing and foliar spraying,the content of malondialdehyde and the production rate of active oxygen species were decreased,and the contents of soluble sugar and soluble protein were increased,which enhanced the stress resistance of the plant.In addition,the application of L-Arginine can also increase the chlorophyll content of leaves,improve the photosynthetic capacity of leaves,and delay leaf senescence.In addition,the application of L-Arginine can also increase the ear length,row number and ear number of corn,reduce the bald tip length and abortion rate,and improve the yield of corn.The treatment with L-Arginine reduced the length of bald tip and the rate of abortion by 22.59% and 40.86%,while the number of grains per ear and yield increased by 41.53% and 13.89%,respectively.In conclusion,different degrees of drought treatment inhibited the photosynthesis of maize leaves,increased the degree of lipid peroxidation of cell membrane,and caused metabolic disorders in cells.Under the drought treatment,the number of grains per ear and the weight of grains decreased,and thus the grain yield decreased.However,L-Arginine treatment could increase the photosynthetic capacity of maize plants under drought conditions,improve the water metabolic balance of maize plants,enhance the antioxidant system,maintain the stability of cell membrane,and thus enhance the drought resistance of maize plants and increase the yield.更多还原