【作者】 于显枫；

【导师】 郭天文； 张仁陟；

【作者基本信息】 甘肃农业大学 ， 植物营养学， 2008， 硕士

【摘要】 以春小麦宁春4号为试验材料,试验在甘肃省农业科学研究院旱地农业研究所的抗旱棚中进行。采用随机区组设计的方法,两因素三水平,三个氮素水平分别为:无氮(CK),不施纯氮;中氮(MN),施纯氮0.06g/kg;高氮(HN),施纯氮0.23g/kg。三个水分处理水平分别为:严重干旱,维持田间持水量的40%;中度干旱,维持田间持水量的60%;正常供水,维持田间持水量的80%。实验共设9个处理组合,每处理重复10次。主要试验结果如下:1、施氮可提高小麦功能叶的叶绿素含量、净光合速率(Pn)、瞬时水分利用效率(IWUE)、气孔导度(Gs)、电子传递速率(ETR)、PSⅡ总的光量子产量(Yield)、光化学猝灭系数(qP),同时胞间CO2浓度(Ci)减小。干旱和正常供水条件下,高氮处理的Pn、IWUE、Gs和ETR均大于其它氮素水平。在拔节期和灌浆期,干旱条件下高氮叶片Yield显著低于中氮和对照处理;在抽穗期和灌浆期,正常供水和中等干旱的高氮叶片qP较对照以及丰水和严重干旱的中氮叶片高。在三种氮素营养水平下,随着水分胁迫的加重,小麦叶片叶绿素含量、类胡罗卜含量、IWUE以及Pn均表现出增大的趋势。在不施氮条件下,随着水分胁迫的加重,小麦叶片Gs、ETR和qP降低,Ci增大。而高氮和中氮水平下,小麦叶片Gs增加、ETR和qP升高,Ci减小。小麦叶片IWUE与Pn呈线性正相关,与蒸腾速率(Tr)、Ci、Gs呈线性负相关。小麦叶片Pn与Yield、qP、ETR表现为显著线性正相关,而且其相关性在中等氮素水平达到最高;Pn与Gs、IWUE之间的相关性因处理不同而异,证明施氮能够显著提高光合机构开放比例、捕捉光量子的能力和电子传递速率,从而改善光合机构效能;氮素对气体交换的影响受水分条件的显著作用,从而影响叶片水分利用效率,但由于干旱导致Pn和IWUE的降低可以通过增施氮肥得到部分补偿。2、施氮可提高小麦功能叶片的超氧化物歧化酶(SOD)、过氧化氢酶(CAT)活性而丙二醛(MDA)含量降低。丰水条件下,拔节期不施氮肥和中氮处理的小麦叶片MDA含量均高于高氮处理的小麦叶片MDA含量,其它表现为随着施氮量的增加而降低。在三个水分条件下,小麦叶片SOD活性表现为从拔节期-扬花期逐渐升高而灌浆期降低,并且随着施氮量的增加而升高。在丰水条件下,小麦叶片CAT活性表现为随着施氮量的增加而升高。在中度干旱条件下,拔节期和扬花期的小麦叶片CAT活性表现为随着施氮量的增加而升高,抽穗期和灌浆期中氮处理的小麦叶片CAT活性表现为最高。严重干旱条件拔节期和灌浆期的小麦叶片CAT活性表现为最高。3种氮素营养水平下,随着水分胁迫的加重,小麦叶片MDA含量,SOD活性升高;在无氮条件下,小麦叶片CAT活性降低,而施氮条件下,小麦叶片CAT活性升高。3、在丰水和干旱条件下,从拔节期—抽穗期,小麦叶片的全N含量均表现为HNW>MNW>CK1。但在严重干旱条件下,总的趋势是从拔节期—灌浆期表现为逐渐降低。从拔节期-灌浆期均表现为MND处理的最高。在拔节期和灌浆期,HND处理的却最低。丰水条件下,扬花期中氮处理的小麦含磷量表现为最高,中度干旱条件下对照和中氮处理的小麦叶片含磷量表现为最高。三个水分条件下,小麦叶片含钾量无明显差异。小麦叶片硝酸还原酶活性(NRA)表现为随着施氮量的增加而增大。NRA与小麦植株含氮量的相关分析表明,NRA与小麦植株含氮量表现为负二次相关的趋势,即随小麦植株含氮量的增高,NRA先表现为降低的趋势,达到最低点,随着小麦植株含氮量的增高,NRA升高。4、在丰水和中度干旱条件下,拔节期的小麦植株高度表现为中氮处理的最高,其它均是高氮处理的最高。在三个水分条件下,千粒重、穗粒数和平均每盆穗粒重均是高氮处理的最大。3种氮素营养水平下,小麦千粒重和每盆穗粒重均表现为中度干旱的为最高;随着水分胁迫的加重,小麦株高、干物重、穗粒数降低。更多还原

【Abstract】 The experiment was conducted in the Institute of Dryland Agriculture, Gansu Academy of Agriculture Sciences. Random block design method was adopted, two factors three levels, the three nitrogen levels were: no nitrogen (CK), didn’t apply pure nitrogen; middle nitrogen (MN), applied pure nitrogen 0.4g per pot; high nitrogen (HN), applied pure nitrogen 1.5g per pot. the three water levels were: Serious dry, maintain 40 percent of saturated water content; Middle dry, maintain 60 percent of saturated water content; Normal Water, maintain 80 percent of saturated water content. There were totally nine treatments, repeated three times. The main conclusions of the study are summarized as follows:1、Nitrogen application could enhance the foliar photosynthetic rate(Pn), instantaneous water use efficiency (IWUE), stomatal conductance (Gs), the apparent photosynthetic electronic transport rate (ETR), overall photochemical quantum yield of PSⅡ(Yield) and photo-chemical quenching coefficient (qP), and decrease intracellular concentration of CO2(Ci). Under drought and well water conditions, the Pn, IWUE, Gs and ETR of high-nitrogen leaf was higher than the other nitrogen level. During Jointing and Ripening periods, the total PSⅡphoto Yield of high-nitrogen leaf which under drought condition were lower than the middle-nitrogen leaf and controls; During Heading and Ripening periods, the qP of high-nitrogen leaf that under middle middle-dry and well water condition were higher than middle-nitrogen leaf in wet and driest treatments. Under the condition of three nitrogen level, with the aggravated of water stress, the Chlorophyll content、carotenoid content、IWUE and Pn demonstrated a trend of increasing。Under the no nitrogen condition, with the aggravated of water stress, Gs、ETR and qP decreased, Ci increased. however, Under the middle and high nitrogen condition, the result was opposite.Correlation analysis showed that there were a significantly linear positive correlation between IWUE and Pn ,but negative with Tr、Ci、Gs. wheat leaves of Pn was positive correlation with Yield、qP、ETR, and reach highest point on the middle nitrogen level; The relationship between Pn and Gs, IWUE were different in different treatments, the results indicated that nitrogen application could improve the opening proportion of photosynthetic instruments, photos-catching ability and electronic transport rate, and then amended the efficiency of photosynthetic instruments; The effects of nitrogen application on gas exchange were different under different moisture condition, and then affected the water use efficiency, but the reduction of Pn and IWUE caused by drought could be compensated by supplying nitrogen fertilizer.2、nitrogen application could enhance the SOD、CAT of Function Leaf, decrease MDA. Under well water conditions, both the MDA of CK and MN treatment were higher than HN treatment during jointing stage, the others showed decrease with the increase of nitrogen application. Under three water conditions, the SOD of wheat leaf gradually increased from jointing stage to flowering stage, and increased with the inhance of nitrogen application. Under well water conditions, the CAT inhanced with the nitrogen increase. Under middle dry conditions, the CAT was increase during Jointing and flowering stage, MN treatment the CAT presented highest during Heading and Ripening stage. Under Serious dry conditions, CAT presented highest duringjointing and ripening stage. Under the condition of three nitrogen level, the more water, the higher MDA and SOD content in the wheat leaves. under the condition of no nitrogen, however, the CAT of the wheat leaves increased in low nitrogen, and it increased while applying nitrogen.3、Under well water and dry conditions ,from jointing stage to heading stage, the content of total nitrogen were HNW>MNW>CK1. Under serious dry conditions, the total tendency was gradually decrease from jointing to ripening stage. And the MND treatment was highest, however, the treatment HND was lowest .under well water conditions, the phosphorus content of nitrogen treatment was highest during flowering stage, middle dry and ck conditions were also highest. Under three water conditions the potassium content has had no significant difference. Correlation analysis showed that there was a twice negative correlation trend between NRA and wheat nitrogen content.4、The trial indicated that, under well and middle dry conditions, wheat height was highest in the middle nitrogen treatment during jointing stage, the others were highest in high nitrogen treatment, as well as 1000-grain weight、grain number per spike and grain weight per spike under three water conditions. Under the condition of three nitrogen level, the more water, the lower height、dry weight and spike number of wheat. Both 1000-grain weight and Spike grain weight per pot of wheat were highest under middle drought treatment.更多还原