【作者】 陈展宇；

【导师】 徐克章；

【作者基本信息】 吉林农业大学 ， 作物栽培学与耕作学， 2008， 博士

【摘要】 为了研究旱稻品种的抗旱特性，选用旱稻品种、抗旱性强水稻品种和抗旱性弱水稻品种为材料，试验于2006～2007年在吉林农业大学试验田进行，在旱作条件下，对三种抗旱性不同的品种进行了解剖结构、光合生理特性、抗氧化系统及渗透调节等方面进行研究。综合研究了旱稻品种抗旱的特性，为进一步利用旱稻抗旱资源和发展旱稻生产提供一定理论基础。主要结果如下：1．旱作条件下，旱稻品种产量最高，平均为5458kg·hm^-2；而抗旱性强水稻品种产量次之，平均为4400kg·hm^-2；抗旱性弱水稻品种产量最低，平均为3355kg·hm^-2。2．开花-灌浆期旱稻品种根后生木质部导管的个数多，导管、中柱面积大，通气组织不发达，而水稻品种通气组织发达；旱稻品种叶片主脉维管束导管数量少，小维管束导管数量较多，总的叶中脉内所含维管束数量及束内导管直径大于水稻品种；旱稻品种与水稻品种的气腔数量相差不大，但旱稻品种气腔面积小，角质层的厚度增大明显；旱稻品种叶片气孔的长度和宽度大，气孔的密度小。这有利于旱稻品种叶片进行气体交换，增加体内水分的运输，减少蒸腾失水，增强抗旱性。3．旱稻品种在不同生育期叶片净光合速率、气孔导度和叶绿素含量均比水稻品种高，净光合速率与气孔导度呈显著正相关变化，与蒸腾速率和胞间CO₂浓度呈负相关变化，与水分利用效率呈极显著正相关。表现为净光合速率较高时胞间CO₂浓度却较低，而气孔导度并不低，说明旱稻品种同化CO₂的能力更强，同时也说明，旱稻品种叶片净光合速率的提高，存在非气孔因素限制。净光合速率、表观叶肉导度与产量呈显著正相关，成熟期相关系数最大(r=0.8965^**，r=0.9962^**)。在开花期、成熟期蒸腾速率与产量呈显著负相关(r=-0.6637^*，r=-0.8284^**)，水分利用效率与产量呈显极著正相关(r=0.8904^**，r=0.8986^**)，说明旱作条件下开花期、成熟期是产量形成的重要时期。在旱作条件下，旱稻减少水分蒸腾，提高水分利用效率高，维持较高的光合生产能力，这是其适应干旱环境维持高产的生理基础。开花-灌浆期旱稻、水稻品种叶片净光合速率与气孔导度的日变化基本一致，净光合速率峰值出现在上午10∶00左右，12∶00时下降，下午14∶00略有回升后持续下降，呈现日下降变化，有光合“午休”现象；蒸腾速率呈单峰曲线，峰值出现在中午12∶00，主要是水分亏缺引起的气孔因素和非气孔因素的影响导致。旱稻品种光合“午休”程度较轻，维持较高的净光合速率。4．与水稻相比，在各个生育期旱稻品种均表现为叶片内丙二醛含量、细胞膜透性较低，超氧化物酶（SOD）活性、过氧化氢酶（CAT）活性和过氧化物酶（POD）活性高；旱稻、水稻品种从苗期到成熟期，SOD活性变化呈先升高，再下降的趋势，CAT活性和POD活性变化趋势与SOD基本一致。在过氧化物酶同工酶电泳图谱中，在生育后期，旱稻品种出现小分子量的POD同工酶谱带。旱稻品种中较高的抗氧化酶活性及高含量的小分子POD同工酶，可以减缓叶片衰老的速度，从而维持高水平的光合作用。5．旱稻品种叶片内可溶性蛋白含量高于水稻品种，旱稻品种可以通过合成可溶性蛋白维持正常代谢活动，适应干旱胁迫，旱稻品种在电泳图谱出现许多小分子的蛋白质谱带，小分子的蛋白质可以调节细胞的渗透性吸水，提高抗旱性；旱稻品种硝酸还原酶活性高于水稻品种，在苗期硝酸还原酶活性最高，但随着生育进程，硝酸还原酶活性下降幅度大，苗期、灌浆期叶片硝酸还原酶活性与可溶性蛋含量呈显著正相关（r=0.6409^*，r=0.5817^*）。6．旱稻品种在整个生育时期均表现脯氨酸含量高，这有利于提高旱稻品种的抗旱性，其含量的大小也反映了不同品种抗旱性的差异。旱稻品种苗期到灌浆期叶片内可溶性糖含量均高于水稻品种，成熟期低于水稻品种，可能在生育前期可溶性糖参与渗透调节。旱稻品种在旱作条件下，生育前期通过合成适量的脱落酸来适应干旱的胁迫，少量的脱落酸调节气孔开关，诱导大量渗透调节物质合成，提高植物抗旱能力，而成熟期旱稻体内脱落酸含量少，减缓衰老。抗旱性弱的水稻品种生育前期体内合成的脱落酸量少，抗旱性差，而成熟期体内脱落酸含量高，加快叶片衰老。通过对不同品种解剖结构以及生理生化指标和产量的相关分析，说明旱稻品种角质层厚度大，光合速率高，蒸腾作用弱，水分利用效率高，具有较高的光合生产能力。此外抗旱性强的水稻品种也适合旱作，可以作为旱稻品种选育的种质资源。叶片净光合速率、硝酸还原酶活性、抗氧化酶活性、POD同工酶、抗旱蛋白、ABA含量和脯氨酸含量可作为筛选抗旱高产旱稻品种的生理生化指标。更多还原

【Abstract】 In order to research the drought resistance of upland rice, upland rice varieties, rice varieties withstrong drought resistance and rice varieties with weak drought resistance were used as experimentalmaterials, carring out in experimental plot of Jilin Agricultural University between 2006 and 2007.Anatomic structure、photosynthesis physiological nature、antioxygen system and osmoregulation of rice andupland rice varieties were studied under dry cultivation conditions. The characteristics of drought resistanceof upland rice varieties were systematically studied, which offered theoretical bases to utilize furtheranti-drought resources and develop production of upland rice. The experimental results were as followed:1. Under dry cultivation condition, the average yield of upland rice varieties was the highest(5458kg·hm^-2); the rice varieties with strong drought resistance was the secondary (4400kg·hm^-2), and therice varieties with weak drought resistance was the lowest (3355kg·hm^-2).2. During the tilling-flowering stage, there were many vessels in deutoxylem of roots, the area ofvessels and stelae were large and aerenchyma was undeveloped in upland rice varieties, but aerenchyma ofrice varieties was developed; The amount of vessels in principal vein vascular of leaf in upland rice varietieswas decreasing, but that of small vessels was increasing and the amount of vascular and total median veindiameter of inner vessels in upland rice varieties were larger than in rice varieties. Upland rice varietiesdidn’t have a big difference from rice varieties in the amount of gas cavity with small area and obviouslyaugmented cuticle thickness. Big length and width but small density of stomata in leaf in upland ricevarieties contribute to exchange gas and increase transportation of water and decrease transpiration andthus enhance the drought resistance.3. Net photosynthetic rate, stomatal conductance and content of chlorophyl of leaf in upland ricevarieties during different periods of duration were all higher than in rice varieties. Net Pn showedsignificantly positive correlation with Gs and significantly negative correlation with transpiration rate、intercellural CO₂ concentration and significantly positive correlation with water use efficiency. When netPn and Gs were high and Ci was lower, which indicate that it was stronger in assimilation CO₂ in uplandrice varieties and continually increasing Pn could also have limited factors from non-stomata in leaves. Theapparent mesophyll conductance showed significantly positive correlation with the yield and correlationcoefficient was the highest (r=0.8965^**, r=0.9962^**) during maturation period. Transpiration rate showedsignificantly negative correlation with the yield (r=0.-6637^**, r=0.-8284^**) during the flowering andmaturation stage. The water use efficiency at flowering stage and maturation stage also showed verysignificantly positive correlation with the yield(r=0.8904^**, r=0.8986^**) and this correlation illustrate that the flowering stage and maturation stage are important stages for yield formation of upland rice under drycultivation condition. Reduction transpiration of water, enhancement the water use efficiency andmaintenance of higher photosynthetic productivity of upland rice varieties under dry cultivation conditionadapte them to drought and became physiological basis of high yield.Daily variation of net Pn and Gs of upland rice varieties and rice varieties was consistent duringfilling-flowering stage, which all showed change of daily depression and photosynthesis midday depressionunder dry cultivation condition. The maximum value of net Pn were measured at 10 am and 12 am declinedand net Pn a little increased in the afternoon14, soon began to decline. Daily variation of Tr showedunimodal curve and peak value occurred at 12 am. Midday depression of photosynthesis had happened wascaused by the effect of water deficit on stomatal and other factors. Upland rice varieties had slight degree ofphotosynthesis midday depression and net Pn was maintained to be higher value.4. The content of malonaldehyde and membrane permeability of leaf in upland rice varieties was lowerthan rice varieties. The activities of superoxide enzyme、catalase and peroxidase were all higher than ricevarieties. The change trend of activity of SOD was firstly increasing and then decreasing and the trend ofCAT、POD were basically consistent with that of SOD. The band of POD isoenzymes with smallmolecular weight in upland rice varieties was presented in POD isoenzymes electrophoresis pattern at latestage. The leaves senescence of upland rice were slower than rice, because upland rice have highantioxidase activities and more POD isoenzymes of small molecular weight which make photosynthesissmoothly.5. The content of soluble proteins in upland rice varieties was higher than in rice varieties showed thatupland rice varieties maintained normal metabolism and adapted them to drought through synthesizingsoluble proteins under drought stress. The band of many soluble proteins with small molecular weight inupland rice varieties was presented in electrophoresis pattern and these proteins could adjust cell toosmotical absorption of water and make drought resistance increasing. The activity of nitrate reductase inupland rice varieties was higher than in rice varieties. At the seedling stage the activity of enzyme was thehighest but had a big decrease accompanying with the process of growth. The activity of nitrate reductaseshowed positive correlation with the content of soluble proteins at seedling stage and filling stage（r=0.6409^*, r=0.5817^*）.6. The content of proline in upland rice varieties were higher than in rice varieties during the wholeperiod of duration, High content of proline contributed to increase drought resistance of varieties, whichthe content of proline reflected the differences in drought resistance among varieties. The solublesaccharides content of leaves was higher than rice varieties from seedling stage to filling stage, but it waslower at maturation stage. Soluble saccharides in leaf might participate in osmoregulation at early periodof duration. The synthesis of opportune abscisic acids adapted upland rice varieties to drought stress and increase drought resistance of plants by which regulated stomata on-off and induced a large amount ofsynthesis of regulatory substances under dry cultivation condition at early period of duration. However,the content of abscisic acid became decreased and slow down insenecence during maturation period. Therice varieties synthesized small amount of abscisic acid had weak drought resistance at early period ofduration, but high content of abscisic acid speeded up insencence at maturation stage.Through analysing anatomic structure、yield and physiological and biochemical indexes, the resultsshow that thick cuticle of upland rice and small stoma density can diminish transpiration, increase WUE,and maintenance higher photosynthesis productivity. Some rice varieties with strong drought resistancecould be suitable for dry cultivation and become germplasm resource for selection of upland rice varieties.In addition, net photosynthetic rate, the activity of nitrate reductase and antioxidase, POD isoenzymes,anti-drought proteins and the content of abscisic acid and proline could be used as physiological andbiochemical indexes for selecting upland rice varieties with high-yield and drought resistance.更多还原