【作者】 葛体达；

【导师】 隋方功；

【作者基本信息】 莱阳农学院 ， 作物栽培学与耕作学， 2004， 硕士

【摘要】 我国玉米主产区主要集中在北方的半干旱和半湿润地区,基本是雨养农业。玉米生长的各个时期均会受到不同程度、难以预料的干旱胁迫,从而导致大幅度减产。因此,有关玉米对干旱胁迫的响应成为当今人们关注的热点问题之一。但以往的田间观测和理论研究多集中于玉米某一生长发育阶段,而对其全生育期的干旱响应的探讨仍然不多,尤其地上、地下部对干旱的适应协调研究不够深入,定量化程度较低。因此,本研究以夏玉米为供试材料,利用大型活动式防雨旱棚,采用池栽试验和室内分析等相结合的研究方法,系统探讨了不同土壤水分条件(充分供水,轻度水分胁迫,严重水分胁迫)对夏玉米生长发育、产量构成性状、品质及水分利用效率等的影响及其生理生化机制。主要研究结果如下:1.水分胁迫对夏玉米生长发育、光合产物积累、运转和分配的影响水分胁迫下,玉米生长发育受到抑制,如株高降低、茎(基)粗变细、叶面积系数减少、根条数变少、根体积变小、叶片出生速度减慢、叶片变小、变窄、叶形指数变大、比叶面积大大降低、硬叶指数和肉质化程度增加。水分胁迫延长了雌雄花期间隔期(ASI),从而在一定程度上延迟了夏玉米的灌浆期,这将致使玉米穗粒发育受到明显阻碍,产量降低。水分胁迫改变了光合产物积累、分配和运转的绝对积累量、累积速率和分配率,即影响过程线的陡度(累积速率)和高度(最大值),但对夏玉米各生育期光合产物积累、分配和运转等的总体趋势影响不大,三种水分处理下均表现出慢—快—慢、低—高—低的变化趋势。本试验系统研究了,在水分胁迫下,夏玉米干物质及其各器官干物质累积速率降低、总量减少,根冠比、根叶比、叶茎比、根茎比发生改变,不同器官干物质转移量、转移率和转移量对雌穗重的贡献有所变化。合理的水分供应可促进玉米植株生育前期光合产物的积累,以及生育后期干物质从营养体向籽粒的转移,在成熟期营养器官中的非结构性碳水化合物滞留少,向籽粒中的运转彻底,可获得较高的籽粒产量。而在水分胁迫下,玉米干物质积累减少,碳代谢发生紊乱,分配、转移到生殖器官的同化物减少。2.水分胁迫对夏玉米生理生化指标的影响水分胁迫下,玉米植株体内生理生化机制发生了明显的变化。玉米叶片相对含水量下降、叶片及根系质膜透性上升,并且根的质膜透性比叶片上升快,根系活力下降,离体叶片保水力降低;光合速率、蒸腾速率减少,且光合速率对水分胁迫的敏感性大于蒸腾速率,玉米冠层中、下部的光合有效辐射(PAR)均显著增加,而其冠层上部因接受太阳辐射的程度基本一致,故其光合有效辐射差异不显著。在水分胁迫下,玉米根系、叶片保护酶系SOD、CAT、POD活性均在生长发育前中期显著升高而后期下降,即保护酶系统对水分胁迫响应的策略不同,前中期如大口期和抽雄前期主要表现为积极应对,后期如灌浆期和乳熟期主要表现为被动忍耐;根系SOD、CAT和POD活性小于叶片。SOD、CAT、POD活性对水分胁迫的敏感程度不同,SOD对水分胁迫不敏感,水分胁迫后期,SOD仍有较高活性,POD活性则明显降低。膜脂过氧化产物MDA含量随水分胁迫程度加剧而增加,且根系MDA含量小于叶片MDA含量。而在水分胁迫下,叶片与根系中可溶性蛋白质含量降低。研究还表明,在水分胁迫下,玉米根系保护酶活性及膜脂过氧化作用对水分胁迫的反应和叶片保护酶活性及膜脂过氧化作用对水分胁迫的反应呈正相关关系,且绝大多数的相关系数达显著或极显著水平。3.水分胁迫对夏玉米籽粒产量、产量构成因素及品质的影响土壤含水量与产量密切相关,在一定范围内,随土壤含水量的减少产量降低。胁迫处理的产量均小于充分供水处理,轻度水分胁迫处理的产量是充分供水处理的77.14%。而严重水分胁迫处理营养体极度削弱,生育进程推迟,穗粒数极少,产量极低,仅为充分供水处理的24.57%,差异达极显著水平。造成减产的主要因素是每穗粒数的减少、百粒重的下降以及经济系数降低。本研究首次提出了严重水分胁迫导致玉米成熟期推迟,其具体表现为,在收获期籽粒、穗轴、苞叶、花丝的含水量均随水分胁迫的加剧而显著升高,严重水分胁迫导致收获期玉米籽粒、苞叶、穗轴、花丝含水量较充分供水约高20%～60%,从而造成收获期雌性生殖器官的贪青晚熟。水分条件在某种程度上影响了玉米籽粒品质。水分胁迫降低了籽粒中淀粉、粗脂肪含量;提高了籽粒可溶性总糖、还原糖、N、P、K、中微量元素Ca、Mg、Cu、Zn、Mn含量。但不同元素的升高比例(增幅)不同。不同元素对水分胁迫响应的顺序为Zn最大、Ca、Mg、Cu次之、Mn最小。4.水分胁迫对玉米耗水特性及水分利用效率的影响随着供水量的减少,夏玉米各生育期的耗水量也相应减少,即各处理各生育期的耗水量均表现为充分供水处理>轻度水分胁迫处理>严重水分胁迫处理,但各处理的模系数基本相同。不同水分处理,夏玉米各生育期内农田耗水强度(日耗水量)过程线基本呈抛物线形状(单峰曲线变化),苗期和成熟期耗水强度较小,抽雄至吐丝期达最大值。各生育期耗水强度随土壤含水量的增大而增大。各生育期(除腊熟期外)叶片水平的水分利用效率基本上随土壤含水量的增加而增加,而在腊熟期呈相反的趋势,即土壤含水量愈低则叶片水分利用效率愈大。而籽粒水分利用效率并不随耗水量的增加而简单的增加,轻度水分胁迫处理的籽粒水分利用效率为最高,其值为1.59 kg·mm-1,比充分供水处理高了19.32%。5.不同水分处理水分效应的综合评判在本试验条件下,模糊综合评判的结果表明:轻度水分胁迫处理(田间持水量的(55±5)%)的水分效应综合评判结果最优;另外,由于严重水分胁迫处理的上述特性和充分供水处理差异显著,而轻度水分胁迫和充分供水不显著,因此可以认为轻度水分胁迫,即土壤含水量为田间持水量的(55±5)%为夏玉米正常生长发育的下限指标,可作为制定节水栽培措施的理论依据。更多还原

【Abstract】 The main planting areas of maize are focus on the semi-drought and semi-wetness regions in the north of China, where the water which use in agriculture mainly depends on the rain, therefore, the drought stress threaten the every and the whole growth stages inevitably and unpredictably, which can reduce the yield to decrease. This is the important reason why the maize yield is not too high and too stable in our country and the other country in the world. Thus it attach more and more importance to the mechanism of response and adaptation under drought stress in maize. But the former research of field observation and theory discussion is focus on some growth stage, And lack of studying the whole growth stage, what’s more the research about adaptation to water stress in the main growth stages and the whole stage in maize is not too deeply, the degree of quantity is relatively low. So, the water content is the single factor in this research, summer maize was selected to study as trial crop, The methods of pool culture in water proof installations and analysis were used to systematic study of effects of the different soil water content (ie. full supply water, a moderate and a severe water stress) on growth and development, yield and it’s component, WUB and the mechanism of physiological and biochemical. The main results were indicated as followings:1. Effects of water stress on growth and development, accumulation, translocation and redistribution of photosynthetic product in summer maizeUnder water stress the growth and development of maize was restrained. The plant height declined, stem diameter, LAI, root volume, the growth speed of leaf etc. were restrained in different degree. And the specific leaf area decreased, while selerophyllous index, succulence degree increased. It can prolong the ASI under water stress, and that it postpone the filling stage in some degree. It hindered the growth of spike and cause yield dropped.Although the total mount of accumulation, translocation, redistribution and transfer rates in the different growth stages were much different under drought, the general trend of accumulation, translocation and redistribution of photosynthetic product of summer maize was not significantly influenced by water deficient, Under water stress, the dry matter of different organs was decreased, the ratios of root to shoot, root to stem, leaf to stem, root to leaf of maize plant were changed. And the amount of dry weight transferred, transfer rate and the percentage of ear weigh in the different organs were changed under drought The proper water supply can effectively promote the dry matter accumulation during the prophase growth stages, and it can also stimulate vegetative organs transfer to grain at the evening of growth stages. This suggested that the remained non-structive carbohydrates in vegetative organs were fewer and the redistributed dry matter mainly contributed to higher grain weight, and thus getting higher corn yields, compared with the other two water treatments.2. Effects of water stress on physiological and biochemical index in summer maizeUnder water stress the internal physiological and biochemical of plant changed distinctly. The leave relative water content and roots vitality decreased, the plasma membrane permeability of leave and roots enhanced under drought stress in maize. Furthermore the root plasma-membrane permeability enhanced more sharply than the leaf. Leave water-holding capacity declined apparently but it will get back the intrinsic characteristic of the specific species at the evening growing stage in maize, consequently it indicate the genetic speciality of the species. Photosynthetic rate and transpiration rate also shut down under water stress, what’s more the Photosynthetic rate was more sensitively than the transpiration rate. And the middle and bottom PAR was enhanced while the top is no difference.Under water stress, activities of superoxide dismutase(SOD), catalase(CTA),and peoxidase(POD) in leaves and roots increased sharply at prophase and metaphase growth stages such as male tetrad stage, while declined at the evening developmental stages such as milky stage, different strategies of maize for coping with water stress under field conditions were found at different growing stages of plant development. At the stage of male tetrad and the pre-tasselling the mechanism response to drought is active while at the stage of filling and milking is forbearing negatively; The protective enzyme activities in root are lower than that in leaves, but the sensitive degree of these enzymes to water stress is different, SOD activities is not sensitivity under drought stress compared with the other to protective enzymes. The content of malondialdehyde (MDA) is increased following the stronger water stress, and also the content of MDA in roots is lower than that in leaves. Under water stress, the soluble protein in roots and leaves is decreased.The protective enzyme activities and lipid peroxidation in root are positively related to that in leaf, and furthermore the most of correlated coefficients show the significant difference.3. Effects of grain yield and it’s components and quality in summer maizeThe water content of soil correlated closely to pod yields,with the decrease of the water content,pod yields declined significantly. The main factors that caused reduction of output were the decreases of the grain number per ear and the drop of weight of 100 grains. Serious water stress can cause postpone the harvest stages, and that become”water corn”. At harvest the water content of grain, spike axe, bract were enhanced sharply under drought stress. Severe water stress would enhance about 20%～60% for the water content of grain, grain axes, bract ,filigree compared to the treatment of full- water supply, and resulted in the postponement of its maturation.Water condition can influence grain quality in some degree. Under water stress, the content of grain starch, crude fat were decreased, while the content of soluble sugar, soluble deoxidize sugar,N,P,K and microelements(Ca,Mg,Cu,Zn,Mn) in grain were improved.4. Effects of water consumption character, water use efficiency (WUB) in summer maizeThe amount of water consumption was decreased at the every growth with the decrease of the water supply, but modulus of water consumption was almost the same under different water treatments. The general trend of water consumption intensity at every growth is a parabola shape(single apex curve) under different water treatments, and it is not big at the stages of seedling and autumn, it got to the maximum at the stages of tassseling and spin. The modulus of water consumption increased by the increase of soil water content. WUB in the lea level enhanced by the increase of soil water content except the milky stage, while WUB in the grain level wasn’t increased by the increase of the amount of water consumption, it is the largest(1.59 kg·mm-1 )under the light water stress treatment M, it improved 19.32% times compared with the treatment of full-water supply.5. Comprehensive judgment of water benefits under different water treatmentsUnder the condition of this experiment, the result of fuzzy comprehensive Judgment showed that the treatment of light water stress((55±5)% of SWC) was the optimum. In addition, Because of the significant difference between severe water stress treatment and sufficient water supplying treatment above characteristic, and insignificant difference between light water stress treatment and sufficient water supplying treatment. The light water stress ((55±5)%)can be as minimum index for normal growth and development of summer maize.更多还原