芒果蒂腐病菌对芒果采后乙烯释放和ACC含量的影响

测定芒果蒂腐病菌(Botryodiplodia theobromae)对芒果果实乙烯代谢的影响,结果表明:B.theobromae在芒果果肉培养基上不产生乙烯,但是B.theobromae代谢活动能诱导芒果果肉中产生大量的1-氨基环丙烷-1-羧酸(ACC),导致芒果快速释放乙烯,随着发病程度增加和贮藏期延长,乙烯释放速率快速增加。高浓度乙烯使芒果果肉快速软化,在25℃条件下,果实在发病后3～5 d就完全腐烂。     

Relationships of Ethylene Evolution Rate and 1-Aminocylopropane-1-Carboxylic Acid Concentration in Grains during Filling Period with Appearance Quality of Rice

To elucidate the relationship between ethylene evolution from the grains and the appearance quality of rice,ten different rice genotypes were used to determine the ethylene evolution rate,1-aminocylopropane-1-carboxylic acid(ACC)concentration in grains during grain filling and the appearance quality of rice,and the effects of chemical regulators on concentrations of ethylene and ACC in the grains during grain filling were also investigated to verify the roles of ethylene in the rice quality formation.The ethylene evolution rates and ACC concentrations in grains during the mid and late grain filling stages were very significantly and positively correlated with chalky kernel percentage and chalkiness.The cultivars with a low ACC concentration in grains exhibited a close amyloplast arrangement and small space between starch granules,whereas those with a high ACC concentration in grains showed a loose arrangement and wide space between the granules.Application of 1μmol/L ACC to panicles at mid and late grain filling stages significantly loosened amyloplast arrangement and increased chalky kernel percentage,chalky area and chalkiness,and the results were reversed when 1μmol/L amino-ethoxyvinylglycine,an inhibitor of ACC synthesis enzyme,was applied to panicles.A practice of moderate dry-wet alternate irrigation reduced ethylene evolution and ACC concentration in grains and thereby reduced chalkiness. The results suggested that ethylene and ACC in grains play an important role in the endosperm structure and appearance quality of rice,and the appearance quality would be improved by reducing ethylene evolution and ACC in grains through either variety breeding and selection,or chemical regulations or cultivation techniques.     

多胺与乙烯对水稻籽粒灌浆、粒重和品质的调控作用

研究水稻产量与品质特性对水稻优质高产育种和栽培具有重要意义。多胺与乙烯作为两类重要的内源植物生长调节物质,对水稻籽粒灌浆充实、粒重和品质形成具有重要的调控作用。本文分别介绍了水稻籽粒多胺与乙烯、灌浆充实、粒重和品质特性,简述了灌浆与粒重和品质形成的关系,重点综述了水稻灌浆期籽粒多胺与乙烯对灌浆充实、粒重和品质(稻米加工、外观和营养品质及籽粒淀粉品质)的调控作用及其生理机制,讨论了存在的问题和今后的研究方向。     

稻米外观与加工品质对大气CO2浓度升高的响应

【目的】大气CO2浓度升高会降低水稻的外观与加工品质。为探明其下降机制并予以缓解，【方法】采用开放式大气CO2浓度升高(FACE)平台、两种栽培品种及其三种不同的基因调控遗传材料 (中花11及其蒸腾调节材料ZmK2.1-15、ZmK2.1-20、OsKAT3-26、OsKAT3-30; 中花11及其促冠根生长材料ERF3-7和ERF3-12; 日本晴及其促硝酸盐吸收材料NIL)，研究稻米外观与加工品质对CO2浓度升高的响应。【结果】稻米外观品质与加工品质对CO2浓度升高的响应因品种不同而异。CO2浓度升高下，中花11的垩白粒率和垩白度增加9.2%和4.4%，整精米率降低5.3%；而日本晴的垩白粒率和垩白度降低11.1%和7.9%，整精米率提升9.8%。蒸腾调节材料显著改善了CO2浓度升高对中花11外观与外观品质的负面效应，与当前CO2浓度相比，CO2浓度升高，ZmK2.1-15、 ZmK2.1-20、OsKAT3-26、OsKAT3-30的垩白粒率相对变化量为−2.7%、−16.3%、−14.8%，+7.4%，垩白度为−8.7%、−22.3%、−15.1%、−3.0%，整精米率为+2.1%、+6.4%、+3.6%、−7.0%。促冠根生长材料加大了CO2浓度升高对中花11号外观与加工品质的负面效应，ERF3-7、ERF3-12的垩白粒率在CO2浓度升高下分别增加17.7%和11.5%，垩白度增加34.4%和19.1%，整精米率分别降低10.1%和0.8%。促硝酸盐吸收材料(NIL)的垩白粒率和垩白度在CO2浓度升高下无明显变化，整精米率下降4.2%。NIL的外观品质较日本晴明显改善，CO2浓度升高下垩白粒率和垩白度分别下降16.5%和17.9%，当前CO2浓度条件下分别下降26.3%和28.9%。【结论】未来CO2浓度升高条件下，通过基因改良促进水稻蒸腾作用和硝酸盐吸收是提升稻米外观与加工品质的有效途径之一。     

稻米外观与加工品质对大气CO2浓度升高的响应

【目的】大气CO2浓度升高会降低水稻的外观与加工品质。为探明其下降机制并予以缓解,【方法】采用开放式大气CO2浓度升高(FACE)平台、两种栽培品种及其三种不同的基因调控遗传材料(中花11及其蒸腾调节材料ZmK2.1-15、ZmK2.1-20、OsKAT3-26、OsKAT3-30;中花11及其促冠根生长材料ERF3-7和ERF3-12;日本晴及其促硝酸盐吸收材料NIL),研究稻米外观与加工品质对CO2浓度升高的响应。【结果】稻米外观品质与加工品质对CO2浓度升高的响应因品种不同而异。CO2浓度升高下,中花11的垩白粒率和垩白度增加9.2%和4.4%,整精米率降低5.3%;而日本晴的垩白粒率和垩白度降低11.1%和7.9%,整精米率提升9.8%。蒸腾调节材料显著改善了CO2浓度升高对中花11外观与外观品质的负面效应,与当前CO2浓度相比,CO2浓度升高,ZmK2.1-15、ZmK2.1-20、OsKAT3-26、OsKAT3-30的垩白粒率相对变化量为?2.7%、?16.3%、?14.8%,+7.4%,垩白度为?8.7%、?22.3%、?15.1%、?3.0%,整精米率为+2.1%、+6.4%、+3.6%、?7.0%。促冠根生长材料加大了CO2浓度升高对中花11号外观与加工品质的负面效应,ERF3-7、ERF3-12的垩白粒率在CO2浓度升高下分别增加17.7%和11.5%,垩白度增加34.4%和19.1%,整精米率分别降低10.1%和0.8%。促硝酸盐吸收材料(NIL)的垩白粒率和垩白度在CO2浓度升高下无明显变化,整精米率下降4.2%。NIL的外观品质较日本晴明显改善,CO2浓度升高下垩白粒率和垩白度分别下降16.5%和17.9%,当前CO2浓度条件下分别下降26.3%和28.9%。【结论】未来CO2浓度升高条件下,通过基因改良促进水稻蒸腾作用和硝酸盐吸收是提升稻米外观与加工品质的有效途径之一。     

Water Management for Improvement of Rice Yield,Appearance Quality and Palatability with High Temperature During Ripening Period

To clarify the optimal water management in large-scale fields under high temperatures at the ripening period, effective water managements during this period for improvement of yield, appearance quality and palatability were investigated. Compared with intermittent irrigation and flooded irrigation, the soil temperature with saturated irrigation remained low throughout the day, and the decrease rate of the bleeding rate of hills was the lowest. These results suggested that the saturated irrigation maintained root activity. For the three irrigation types, the number of spikelets per m² and 1000-grain weight were similar, however, saturated irrigation resulted in significantly higher rice yield due to improvement in the percentage of ripened grains. The saturated irrigation produced a high percentage of perfect rice grains and thicker brown rice grain, furthermore, the palatability of cooked rice was excellent because protein content and hardness/adhesion ratio were both low. Thus, under high-temperature ripening conditions, soil temperature was lowered and root activity was maintained when applying saturated irrigation after heading time. The results indicated that saturated irrigation is an effective countermeasure against high-temperature ripening damage.     

水稻籽粒不同部位植酸含量及其与稻米品质的相关性

 选用13个不同类型的水稻品种,对其籽粒不同部位植酸含量品种间差异及与稻米主要品质性状间的相关性进行了分析。结果表明,供试13个水稻品种米糠、糙米、颖壳、精米的植酸含量平均值分别为48.51、9.77、1.40和0.91 mg/g,而且不同水稻品种间籽粒不同部位的植酸含量存在极显著差异。在籽粒中,米糠中植酸积累最多,其次是精米,颖壳最少。米糠中植酸含量与糙米和颖壳中植酸含量呈极显著正相关。糙米和米糠中植酸含量与稻米蛋白质含量均呈显著的负相关,与千粒重均呈显著正相关。     

结实期干湿交替处理对稻米品质的影响及其生理机制

 以扬稻6号和武育粳3号为材料,研究了结实期干 湿交替处理对稻米品质的影响及其机理。结果表明,结实期轻度干 湿交替处理改善了稻米的加工品质和外观品质,提高了米粉的崩解值,降低了消减值,而重度干 湿交替处理结果则相反。轻度干 湿交替处理还提高了籽粒中蔗糖合酶(SuSase)、ADP葡萄糖焦磷酸化酶(ADPGase)、可溶性淀粉合酶(SSSase)和淀粉分支酶(Q酶)的活性。重度干 湿交替处理则降低上述酶类的活性。上述酶类活性与稻米主要品质指标显著相关。根系伤流中1 氨基环丙烷 1 羧酸（ACC,乙烯合成前体）浓度、籽粒中ACC浓度和乙烯释放速率在轻度干 湿交替处理条件下均明显降低,而在重度干 湿交替处理条件下则明显提高。根系伤流中ACC浓度、籽粒中ACC浓度和乙烯释放速率与SuSase、ADPGase、SSSase和Q酶活性呈显著或极显著负相关。灌浆结实期土壤水分处理改变了根系ACC浓度,影响了籽粒乙烯释放速率和ACC浓度,进而影响籽粒蔗糖 淀粉代谢途径关键酶的活性,最终影响了稻米品质的形成。     

不同籼稻颖果发育及其结构与品质性状

比较了两个籼稻品种颖果的发育,籽粒的主要品质性状以及胚乳淀粉体的大小、形状、结构等特性。结果表明： 扬稻6号的主要品质性状优于湘早籼33;在开花后前期扬稻6号干物质积累速率较慢,但在后期较快,淀粉充实度较高; 淀粉胚乳细胞内存在两种淀粉体,即单粒淀粉体,直径2.4~8.0 μm,平均4.7 μm;复合淀粉体,即由多个单粒淀粉体结合而成,直径5.7~19.5 μm,平均9.7 μm。湘早籼33单粒淀粉体多数为椭圆形或圆球形,大小差异较大,排列疏松,变异系数较大;扬稻6号胚乳单粒淀粉体基本为晶体多面形,发育良好,大小较为一致,排列紧密,变异系数较小。胚乳背部淀粉体的发育和排列结构优于腹部和中部。胚乳垩白的出现是由于淀粉体发育不良、排列疏松所致,而淀粉体的充实又与灌浆物质的输入途径紧密相关。