【作者】 窦永秀；

【导师】 郎有忠；

【作者基本信息】 扬州大学 ， 作物栽培学， 2008， 硕士

【摘要】 2005~2007年三年间以两优培九,扬稻6号,日本晴等水稻品种为供试材料,分析了茎秆抗倒机械力学指标在水稻茎秆上的实际应用,就结实期茎秆结构特征的变化及其与抗折力关系进行深入探讨,并研究不同时期倒伏对水稻产量和稻米品质的影响,主要结果如下:(1)通过茎秆倒伏指标力学分析模型,实际分析供试11个品种的抗折安全系数,对各品种基部第二节间进行分析,与常用的茎秆拉力进行相关分析的结果表明,两指标存在极显著的正相关,节间安全系数与实测值吻合度高,用该评价方法分析水稻茎秆的抗倒性,具有较高的实用价值。(2)水稻茎秆有叶鞘包被和去除叶鞘后的抗折力矩比值在结实期表现的相对平稳,故本文主要研究无鞘茎秆各节间的抗折性。结实期各节间抗折力矩的方差分析结果表明,穗后30天的抗折力矩最小,有较大倒伏风险;越靠近茎秆基部的节间抗折力矩越大。对水稻茎秆基部第二节间的内、外径和茎壁厚度进行方差分析,发现各品种各时期的内、外径都存在一定差异,但有些茎秆细的品种却抗倒,茎秆粗的不一定抗倒,经过进一步分析后得出茎壁厚度对茎秆的抗折性影响较大的结论,增加基部节间的茎秆壁厚,能有效防止水稻倒伏。茎秆壁厚与外径的比值从齐穗后15天到45天变化幅度较小,相对齐穗期显著升高。茎秆中可溶性糖在不同品种、不同节间、不同生育期的含量均有一定的变化,但是没有明显的规律性;通过对淀粉含量的方差分析说明,茎秆中淀粉等主要贮藏在上部节间,基部节间在结实期营养贮藏方面功能渐弱,而主要担负植株的支撑作用;可用性糖含量在水稻茎秆中的变化情况可见,穗后30天可用性糖的含量相对前一时期显著降低;纤维素作为维持茎秆中细胞壁机械支撑特性的最主要成分,它的变化规律是越到茎秆基部,纤维素含量越高,越不容易产生倒伏。对抗折力矩和抗折力各影响因子作相关性分析后得出茎秆壁厚与纤维素含量分别与抗折力呈显著和极显著正相关,生产上若片面追求茎秆粗大而忽视茎壁厚度等指标是不可取的,纤维素含量多少对茎秆抗倒性有较大影响的观点也应受到一定重视。(3)倒伏对供试品种产量的影响表现为,倒伏时期越早,产量越低,结实期的早中期倒伏,对产量有严重影响。产量构成因素中结实率、千粒重受倒伏时期的影响巨大。稻米的加工品质中,出糙率随倒伏时期的变化较稳定,没有太大差异;倒伏越迟,精米率越高,各处理间差异显著;整精米率变化趋势与精米率一致,但各处理间差异较精米率更明显。就外观品质而言,倒伏时期对米粒的长、宽等基本形状无显著影响;垩白粒率和垩白度均表现为随倒伏时期推迟而降低的趋势。从稻米的营养品质看,直链淀粉含量随倒伏时期的推迟呈下降趋势,倒伏越早的直链淀粉含量越高,品质变劣越明显;越早倒伏的稻米,其蛋白质含量越高,食味下降。胶稠度的变化受品种不同而差异较大,胶稠度指标总体较高的品种受倒伏影响小,胶稠度总体较低的品种随倒伏时间的推移胶稠度增加;糊化温度各品种的变化不一致;各品种(组合)稻米随倒伏时间的延迟,均表现出较为一致的峰值黏度及崩解值变大、消减值减小的趋势。更多还原

【Abstract】 From 2005 to 2007, more than twenty varieties were used as materials, in the research on the effect of different lodging stage on rice yield and rice quality, the application of stem lodging resistance mechanics index in rice stem, and on the relationship between variety of stem structure character and fracture force resistance ,the results were as follows:(1) In the mechanics analysis model of stem lodging index, analysis lodging resistance safety coefficient of 11 rice varieties, the result of correlation analysis in the second basal internodes indicated that, compared with stem pull, these two indexes are in positive and significant correlation, safety coefficient in stem node is in high marching rate with real measured result, it is in high utility value when analysis rice lodging resistance in this model.(2)The ratio of lodging resistance moment between Rice stem with leaf sheath and without leaf sheath is stable during productive phase, so the main analysis here is the lodging assistance of stem without sheath. ANOVA of lodging resistance moment of stem node indicated that, lodging resistance moment is the smallest in 30 days after heading, lodging risk is rather heavy; in basal internodes, the lodging resistance moment is bigger. ANOVA of inner diameter, outer diameter and stem wall thickness indicated that, there is some difference in both inner and outer diameter, some stems are thin but can resist lodging, some stems are thick but can’t resist lodging, in further analysis, the stem wall thickness greatly effected stem lodging resistance, enhance the stem wall thickness of basal internodes can effectively prevent lodging. The ratio of stem wall thickness to outer diameter changed in a small range from 15 days after tassel period to 45 days. it is significantly increased than tassel period. the starch in mainly in the upper internodes, the steerage function of basal internodes is decreasing, mostly take on the supporting function; the content of usable carbohydrate(soluble sugar+ starch) is significantly decreased in 30 days after tassel period. Cellulose as the most important basis in supporting stem cell walls, the more close to the basal internodes, the more resistance of stem. The correlation analysis indicated that, both stem wall thickness and cellulose content is in positive significant correlation with lodging resistance moment.(1) The effect of lodging to rice yield indicated that, lodging earlier, the yield getting lower, when lodging appears in early productive stage, it greatly effect grain yield. seed-setting rate and 1000-grain weight these two yield components are effected by lodging. In rice machining quality, brown rice rate is stable during different lodging stage; Lodging later ,the head milled rice rate getting higher, there are significant differences among treatments; the changing trend of full head milled rice rate and head milled rice rate is identically, but the difference among treatment of full head milled rice rate is more significant. In appearance quality, there is no significant effect to the length and width of rice grain among different lodging stage; chalk grain and the ratio of chalky grain are decreasing with the deferring of lodging stage. In the nutrition quality of rice, the content of amylase is decreasing when lodging later, if lodging earlier , the content of amylase and protein is higher ,the quality is getting worse; when the grain in low gel consistency ,with the deferring of lodging stage , gel consistency will increase, when the grain in high gel consistency, it is little effected by lodging stage; with the deferring of lodging stage, all the three rice variety are in the same changing trend , peak viscosity and break down are increasing, set back is decreasing.更多还原