Hormonal changes are related to the poor grain filling in the inferior spikelets of rice cultivated under non-flooded and mulched condition

Non-flooded plastic mulching cultivation (PM) of rice can save much irrigation but usually exhibits a poor grain filling and low grain weight when compared to traditional flooding cultivation (TF). This study measured the variations of plant hormones during grain filling and investigated whether they were related to the grain-filling problem under mulching in a field experiment. Hormonal levels in the grains and the grain development of both superior (early flowered) and inferior spikelets (later flowered) were monitored continuously during the grain filling period. The contents of indole-3-acetic acid (IAA), zeatin riboside (ZR) and abscisic acid (ABA) were higher in superior grains than in inferior ones at early grain-filling stage. For individual spikelets, the peaks of IAA and ZR contents appeared just before the peak grain-filling rate but the peak ABA content matched it. The earlier flowered superior spikelets did not show much difference in grain filling characteristics and hormonal changes under the two cultivation treatments. Distinctively with the inferior spikelets in a panicle, PM led to lower grain weight, higher grain-filling rate at early stage and shorter active grain-filling period than the TF. PM also resulted in less IAA and ZR but more ABA contents in the grains than TF at early and middle grain filling stages in these inferior spikelets. Peaks of these hormone contents in the PM inferior grains usually appeared earlier and also disappeared more quickly than those in TF inferior grains. When exogenous IAA was applied to plants at the initial grain-filling stage, IAA and ZR were increased and ABA was reduced in the inferior grains. The treatment prolonged the active grain-filing period and reduced the peak grain-filling rate of inferior grains, similarly as the case with TF. As a result, IAA spraying enhanced the weight of PM inferior grains but reduced that of TF ones. Exogenous ABA spraying led to the opposite effects to those of IAA. The results suggest that the shortened grain-filling period in the inferior grains under PM is related to the increased ABA and reduced IAA and ZR in the grains. Regulation of the ratio of ABA to IAA in grains could potentially increase the weight of inferior grains under the water-saving cultivation with film mulching.     

杂交粳稻屉优418及其亲本灌浆期叶片内源激素含量变化与衰老之间的关系

以杂交水稻屉优418及其亲本屉锦和C418为材料,研究了生育后期叶片内源激素含量变化与衰老之间的关系。结果表明杂交水稻及其亲本剑叶中ABA、GA1/3、ZR和IAA含量变化趋势基本一致。3个材料的（GA1/3+ZR+IAA）/ABA的比值变化总的趋势也基本相同,前期较平稳,后期比值迅速下降。在生育后期,屉优418和C418的（GA1/3+ZR+IAA）/ABA比值下降速率较慢,与衰老相对较慢一致;而屉锦的（GA1/3+ZR+IAA）/ABA比值下降速率较快,与其衰老较快相一致。     

Relationship Between Changes in Leaf Endogenous Hormone Contents and Senescence During Grain Filling Stage of a Rice Hybrid and its Parents

A major problem in hybrid rice production is the occurrence of leaf senescence during the grain filling stage that can result in reduction of yield. Changes in contents of several endogenous hormones are related to leaf senescence. The relationship between endogenous hormones and leaf senescence in the rice hybrid Tiyou 418 and its parents Tijin and C418, was undertaken for investigation. Indicators of leaf senescence, including superoxide dismutase (SOD) activity, malondialdehyde (MDA) accumulation and chlorophyll content, as well as the contents of abscisic acid (ABA), zeatin riboside (ZR), gibberellin (GA1/3) and auxin (IAA) in the leaves were determined. Different rates of leaf senescence were observed in the three materials. Senescence occurred earliest and fastest in Tijin, followed by Tiyou 418 and then C418. A similar trend was recorded in ABA, ZR, and IAA contents during the grain filling stage in the three materials. Changes in (GA1/3 ZR IAA)/ABA ratios were also similar, being quite stable during the early stage of leaf senescence, and decreasing markedly during the late stage. The ratio declined more dramatically in Tijin, in accordance with its faster leaf senescence. The results suggest that the ratio of (GA1/3 ZR IAA)/ABA regulates chlorophyll content, SOD activity, MDA content and membrane lipid peroxidation. It is postulated that endogenous hormones may play a role in the regulation of leaf senescence in a systematic way.     

Relationship Between Changes in Leaf Endogenous Hormone Contents and Senescence During Grain Filling Stage of a Rice Hybrid and its Parents

A major problem in hybrid rice production is the occurrence of leaf senescence during the grain filling stage that can result in reduction of yield. Changes in contents of several endogenous hormones are related to leaf senescence. The relationship between endogenous hormones and leaf senescence in the rice hybrid Tiyou 418 and its parents Tijin and C418, was undertaken for investigation. Indicators of leaf senescence, including superoxide dismutase (SOD) activity, malondialdehyde (MDA) accumulation and chlorophyll content, as well as the contents of abscisic acid (ABA), zeatin riboside (ZR), gibberellin (GA1/3) and auxin (IAA) in the leaves were determined. Different rates of leaf senescence were observed in the three materials. Senescence occurred earliest and fastest in Tijin, followed by Tiyou 418 and then C418. A similar trend was recorded in ABA, ZR, and IAA contents during the grain filling stage in the three materials. Changes in (GA1/3 ZR IAA)/ABA ratios were also similar, being quite stable during the early stage of leaf senescence, and decreasing markedly during the late stage. The ratio declined more dramatically in Tijin, in accordance with its faster leaf senescence. The results suggest that the ratio of (GA1/3 ZR IAA)/ABA regulates chlorophyll content, SOD activity, MDA content and membrane lipid peroxidation. It is postulated that endogenous hormones may play a role in the regulation of leaf senescence in a systematic way.     

齐穗至乳熟期不同温度对水稻南粳9108籽粒激素含量、淀粉积累及其合成关键酶活性的影响

【目的】为了明确灌浆结实前中期不同温度对晚粳稻籽粒灌浆、总淀粉及其组分含量的影响特征及其机理,【方法】以优质食味粳稻南粳9108为材料,利用植物培养箱控温,于水稻灌浆结实期设置高温(HT,日均温度31℃)、中温(MT,日均温度26℃)和低温(LT,日均温度21℃)三个处理,以自然温度为对照(CK),研究灌浆结实前中期持续高低温对晚粳稻籽粒灌浆、内源激素含量、淀粉及其及合成关键酶活性的影响。【结果】随温度上升(21℃～31℃),晚粳稻结实率和千粒重降低;灌浆前中期籽粒总淀粉积累速率加快,但持续时间短,总含量降低,而直链淀粉含量及其所占比例在整个灌浆期均呈降低趋势;灌浆前中期脱落酸(ABA)含量显著增加,赤霉素(GA3)含量降低,玉米素核苷(ZR)含量呈"先增先降"趋势;MT处理有利于提高灌浆结实期籽粒生长素(IAA)含量,HT和LT处理均降低籽粒IAA含量,LT处理下,IAA含量先降后升,而HT处理籽粒IAA含量一直处于较低水平;籽粒可溶性淀粉合成酶(SSS)活性与ZR变化规律相似,也呈"先增先降"趋势,但二者在灌浆结实期并不同步;淀粉分支酶(SBE)活性增加而淀粉脱分支酶(DBE)活性降低。【结论】不同温度显著影响晚粳稻籽粒内源激素含量和淀粉合成关键酶活性的变化,进而影响晚粳稻籽粒灌浆、总淀粉及其组分的积累。     

超级稻花后强、弱势粒淀粉合成相关酶活性和激素含量变化及其与籽粒灌浆的关系

 种植4个超级稻品种\[两优培九和Ⅱ优084（杂交籼稻）、淮稻9号和武粳15（粳稻）\]和2个高产对照品种\[汕优63（杂交籼稻）和扬辐粳8号（粳稻）\],观察其结实期强、弱势粒中蔗糖合酶（SuSase）、腺苷二磷酸葡萄糖焦磷酸化酶（AGPase）、淀粉合酶（StSase）和淀粉分支酶（SBE）活性及玉米素+玉米素核苷（Z+ZR）、3 吲哚乙酸（IAA）和脱落酸（ABA）含量的变化,并测定了强、弱势粒灌浆速率。结果表明,超级稻品种强势粒的最大灌浆速率、到达最大灌浆速率的时间、平均灌浆速率和糙米重与对照品种差异较小,超级稻品种弱势粒的灌浆速率和糙米重显著低于对照。灌浆期强、弱势粒的SuSase、AGPase 、StSase 和SBE活性变化及Z+ZR、IAA 和ABA 含量变化均呈单峰曲线。弱势粒的SuSase、AGPase、StSase 和SBE的峰值活性和平均活性及其Z+ZR 和IAA的峰值含量和平均含量均低于强势粒。弱势粒的ABA 峰值含量和平均含量显著高于强势粒,超级稻品种高于对照品种。籽粒灌浆速率与SuSase、AGPase和StSase 活性及Z+ZR 和IAA含量均呈显著或极显著正相关,与SBE活性及ABA含量的相关不显著。说明超级稻品种弱势粒中较低的SuSase、AGPase和StSase活性及较低的Z+ZR和IAA含量是其灌浆速率小、粒重轻的一个重要原因。     

Relationships Between Barley Hordeins and Malting Quality in a Mutant of cv. Triumph I. Genotype by Environment Interaction of Hordein Content

The genetic (G), environmental (E) and G×E effects on total grain protein and hordein fractions, have been studied in a mutant (TL43) and its parent cultivar, the malting barley Triumph, in various seasons at Dundee (E Scotland) and Lleida (NE Spain). The grain protein content of TL43 was consistently about 2% higher than that of Triumph across environments. Differences in hordein composition were shown by SDS-PAGE electrophoresis. TL-43 had three B-hordein bands not present in Triumph which had a further three bands of the same hordein group not present in TL43. TL43 showed higher B-hordein content than Triumph in Scotland but lower in Spain, whereas the mutant showed consistently higher C- and D-hordein content than Triumph across environments, i.e. there was crossover G×E interaction for B-hordein and non-crossover for C- and D-hordein content. There were also differences in grain ultra-structure between the two lines, as TL43 showed a more dense protein matrix than Triumph, together with thinner pericarp, testa and aleurone layers. It was concluded that the mutation in TL43 had a significant effect on storage protein composition.     

植物激素对杂交稻籽粒灌浆及蔗糖合酶活性的影响

 以亚种间杂交稻两优培九和品种间杂交稻汕优63为材料,对籽粒灌浆期间的内源激素含量和酶活性进行了测定分析,并结合外源激素对水稻籽粒灌浆过程的调控试验,分析了脱落酸对蔗糖代谢关键酶——蔗糖合酶活性的调节作用。结果表明,灌浆前期强势粒中生长素、玉米素核苷和脱落酸（ABA）含量明显高于弱势粒,并与籽粒最大灌浆速率、平均灌浆速率、籽粒充实率和粒重均呈显著或极显著正相关。强势粒中蔗糖合酶活性明显高于弱势粒,且达到峰值的时间也早于弱势粒。籽粒灌浆速率、籽粒充实率、粒重和淀粉积累速率与蔗糖合酶活性呈显著正相关。花后8 d对稻株喷施低浓度ABA显著提高了籽粒中ABA含量和蔗糖合酶活性,增加了粒重和籽粒充实率。喷施ABA合成抑制剂氟草酮作用则相反。上述结果说明,植物激素尤其是ABA对水稻籽粒灌浆有重要的促进作用,其作用在很大程度上是通过调节籽粒蔗糖合酶活性实现的。     

氮肥后移对春玉米子粒灌浆特性及内源激素的影响

以陕科9号为材料,2019～2020年在陕西榆林灌溉区进行大田试验,在总施氮量相同、基肥和大喇叭口期追肥分别占总施氮量20%和40%条件下,设置4个施氮处理,传统施氮(拔节肥40%,N1)、氮肥后移10%(拔节肥30%+花粒肥10%,N2)、氮肥后移20%(拔节肥20%+花粒肥20%,N3)和氮肥后移30%(拔节肥10%+花粒肥30%,N4),分析各处理子粒灌浆特性、内源激素含量和产量构成。结果表明,氮肥后移各处理2年玉米产量均显著高于传统施肥,N3处理产量最高。氮肥后移增加子粒灌浆速率最大时生长量(W_max)、最大灌浆速率(G_max),延长子粒灌浆活跃期;氮肥后移过量(N4),子粒灌浆参数受到不良影响。同时,N3处理子粒生长素(IAA)含量达到峰值时均较N1处理显著增加51.7%,玉米素(ZR)含量显著增加16.7%,赤霉素(GA₃)含量显著增加28.9%,脱落酸(ABA)含量显著降低18.2%。在陕西灌溉春玉米区,总施氮量270 kg/hm²时,拔节期追肥54 kg/hm²、大喇叭口期追肥108 kg/hm²、花后7 d追肥54kg/hm²为该区玉米高产的优化施氮制度。     

六倍体小黑麦株高形成中内源激素含量的变化

为了解六倍体小黑麦株高形成与内源激素的关系,以六个不同株高的六倍体小黑麦品种（系）为材料,对小黑麦在株高形成时期叶片中内源激素含量的动态变化进行了分析。结果表明,矮秆小黑麦品种的ABA、ZR和GA含量在所调查时期均显著高于高秆品种,而IAA含量在生长后期则显著低于高秆品种。同时高秆小黑麦中IAA/ABA、GA/ABA与（IAA＋GA）/ABA的比值均高于矮秆小黑麦,但ZR/IAA、ZR/ABA比值的变化趋势则与IAA、GA含量的变化趋势相反。可见不同株高类型的小黑麦在株高形成过程中内源激素具有显著差异。     

杧果花期内源激素含量的变化

对白玉杧和泰国金白花2个品种杧果在花芽膨大期、初花期、盛花期和末花期的内源激素脱落酸（ABA）、吲哚乙酸（IAA）、赤霉素（GA3）和玉米素核苷（ZRs）的含量进行了研究。结果表明：花芽膨大期金白花中ABA和LAA含量高于白玉杧,而白玉杧中GA3和ZRs含量高于金白花杧;初花期白玉杧中ABA和GA3含量高于金白花杧,而IAA和ZRs含量则低于金白花杧;盛花期白玉杧中ABA,IAA和GA3含量低于金白花杧,而ZRs含量高于金白花杧;末花期白玉杧中ABA,LAA,GA3和ZRs含量均低于金白花杧。     

灌浆期低温对离体玉米子粒灌浆过程及内源激素的影响

以郑单958为材料,采用子粒离体培养方法,研究灌浆期低温对玉米强、弱势粒灌浆特性及内源激素的影响。研究表明,灌浆期低温分别减缓强、弱势粒平均灌浆速率15%、23%,延长灌浆时间约8 d,最终粒重分别降低3%、9%。低温处理下,GA_3、IAA、ZR含量与灌浆速率显著相关;受低温影响,强、弱势粒的激素含量变化趋势相近,与常温相比,子粒GA_3含量先增加后减少,IAA、ZR含量低于对照,且对弱势粒的影响大于强势粒。低温对内源激素含量的影响是导致灌浆速率降低的主要原因之一。     

Changes in Enzyme Activities Involved in Starch Synthesis and Hormone Concentrations in Superior and Inferior Spikelets and Their Association with Grain Filling of Super Rice

The changes in activities of key enzymes involved in sucrose-to-starch conversion and concentrations of hormones in superior and inferior spikelets of super rice were investigated and their association with grain filling was analyzed.Four super rice cultivars,Liangyoupeijiu,IIyou 084,Huaidao 9 and Wujing 15,and two high-yielding and elite check cultivars,Shanyou 63 and Yangfujing 8,were used.The activities of sucrose synthase (SuSase),adenosine diphosphoglucose pyrophosphorylase (AGPase),starch synthase (StSase) and starch branching enzyme (SBE),and the concentrations of zeatin + zeatin riboside (Z + ZR),indole-3-acetic acid (IAA) and abscisic acid (ABA) in superior and inferior spikelets were determined during the grain filling period and their relationships with grain filling rate were analyzed.Maximum grain filling rate,the time reaching the maximum grain-filling rate,mean grain filling rate and brown rice weight for superior spikelets showed a slight difference between the super and check rice cultivars,but were significantly lower in the super rice than in the check rice for inferior spikelets.Changes of enzyme activities and hormone concentrations in grains exhibited single peak curves during the grain filling period.The peak values and the mean activities of SuSase,AGPase,StSase and SBE were lower in inferior spikelets than in superior ones,as well as the peak values and the mean concentrations of Z + ZR and IAA.However,the peak value and the mean concentration of ABA were significantly higher in inferior spikelets than in superior ones and greater in the super rice than in the check rice.The grain filling rate was positively and significantly correlated with the activities of SuSase,AGPase and StSase and the concentrations of Z + ZR and IAA.The results suggested that the low activities of SuSase,AGPase and StSase and the low concentrations of Z + ZR and IAA might be important physiological reasons for the slow grain filling rate and light grain weight of inferior spikelets in super rice.     

干旱胁迫下小麦颖果内源激素的变化及其与胚乳发育的关系

为探明干旱胁迫下小麦颖果内源激素与胚乳发育的关系,以小麦品种扬麦16为材料,在幼苗返青至颖果成熟阶段进行干旱处理,采用树脂切片及显微摄影等技术观察小麦颖果和胚乳细胞发育的形态结构特征,并通过酶联免疫吸附法测定颖果生长素(IAA)、脱落酸(ABA)、赤霉素(GA_3、GA_4)、玉米素核苷(ZR)、二氢玉米素核苷(DHZR)的含量。结果显示,干旱胁迫缩短了小麦颖果发育进程,促进颖果早衰,导致颖果发育不良;显著降低了籽粒千粒重、可溶性糖含量和总淀粉含量,提高了蛋白质含量;促进颖果发育早期胚乳细胞分裂和淀粉积累,抑制了发育后期胚乳细胞的分裂、体积扩大和淀粉体充实,并提高了颖果整个发育过程中胚乳蛋白体的积累;提高了颖果发育前期IAA、GA_3、GA_4、ZR和DHZR的含量,ABA含量在整个发育时期均较高。说明干旱胁迫能通过影响颖果内源激素的积累来调控胚乳发育。     

赤霉素诱导甘蔗节间伸长与内源激素变化的关系

探讨外源赤霉素对甘蔗节问伸长的效果及其与茎尖内源激素的变化关系.试验以新台糖22号为材料,在伸长初期以200 mg/L浓度的赤霉素进行叶面喷施,对照喷清水.结果表明,赤霉素处理的株高在各个时期显著高于对照,而且在处理后7,14和28 d分别比对照提高了17.32%、14.50%和8.35%.赤霉素处理引起植株表现的高度优势一直保持到后期,节间伸长效果主要集中在中部.赤霉素处理的CA,含量显著高于对照:ABA含量则相反,赤霉素处理的均显著低于对照.赤霉素处理的乙烯释放量稍低于对照,IAA含量从第7 d开始稍高于对照的;赤霉素处理对ZR含量的影响不明显.赤霉素处理的ABA/LAA的比值显著下降,ZMAA和EH.IAA的比值也有一定程度的下降,而提高了GA_3/IAA的比值.这说明外源赤霉素促进甘蔗节间的伸长可能主要通过调节ABA和赤霉素含量,其次是乙烯释放量和生长素含量,最终达到调节节间伸长效果.     

化控剂对玉米光合、激素及茎秆力学特性的影响

以东农253为试验材料,在玉米9叶期喷施密高和KP(主要成分DCPTA和ETH),在玉米5个生育时期测定叶片光合酶活、内源激素及茎秆力学特性参数,并进行测产及相关性分析,探究大田条件下化控剂对玉米生长发育的影响。结果表明,喷施密高和KP后叶片SPAD、P_n、RuBPc和PEPc显著提高,增加叶片IAA、GA和ZR含量并降低ABA含量。玉米茎秆单位节间长度干物重、穿刺强度、横折强度和田间致倒伏推力有所增大,降低扁率及子粒含水量,密高和KP处理下玉米产量分别增加6.47%和9.23%。相关性分析表明,除ABA含量与产量呈显著负相关外,光合和其他激素指标呈显著正相关,PEPc、SPAD在完熟期与产量相关性最大,RuBPc在乳熟期与产量相关性最大,P_n在灌浆初期与产量相关性最大。     

同色兜兰叶片内源激素变化与开花关系研究

近些年兜兰产业发展迅速,但花期调控难成为限制兜兰产业发展的瓶颈。以较易开花的同色兜兰为试验材料,观测各时期功能叶长和宽及花朵发育的形态变化,并采用酶联免疫法检测功能叶片内源激素的变化动态,分析它们与花发育的关系。结果表明：（1）同色兜兰花苞显现期,功能叶具有高水平的ZR和低水平的IAA,以利于成花分化;（2）在激素平衡研究中发现,顶芽从营养生长向生殖生长转换时（大苗期）,功能叶具有高比值的 IAA/GA₃、ABA/GA₃和低比值的ZR/ABA、ZR/IAA;（3）成花形态分化时（花苞显现期）,功能叶具有低比值的IAA/ABA、IAA/GA₃和高比值的ZR/GA₃、ZR/IAA;（4）大苗期、花苞显现期内源激素水平和比值对同色兜兰花芽诱导和花芽正常分化具有重要影响。     

自然干旱胁迫下配方肥增效剂对水稻内源激素的影响

 为揭示土壤自然干旱条件下配方肥增效剂对水稻植株内源激素的影响，以中稻培两优93为材料，采用盆栽法研究了配方肥增效剂对水稻内源脱落酸（ABA）、生长素（IAA）、赤霉酸（GA3）、玉米素核苷（ZR）的影响。干旱处理后，ABA在前期大量积累，后期呈下降趋势。根系和叶片中ABA含量大幅度升高，其中根系中ABA增幅达58~101倍，根源ABA积累幅度远高于叶源ABA积累幅度，而增效剂处理促进了ABA的积累。干旱胁迫前，增效剂处理水稻植株根系IAA、ZR和叶片GA3均显著高于对照；而干旱胁迫后，增效剂处理植株上述激素水平均大幅下降，而对照下降幅度较小。叶中IAA、ZR和GA3的变化则与根系相反。     

分蘖期不同基因型宿根甘蔗内源激素的测定

对9个甘蔗品种叶片进行生长素、赤霉素、细胞分裂素、脱落酸4种内源激素免疫测定。结果表明:不同的基因型具有不同的激素含量,品种间差异较大。其中,台糖134生长素含量最高,云蔗89/151的赤霉素和细胞分裂素含量最高,Co331的脱落酸含量最高;粤糖93159的生长素和脱落酸含量最低,桂11的赤霉素含量最低,云蔗71/388的细胞分裂素含量最低。     

自然低温对茶树内源激素含量的影响

以南京中山陵茶园中十年生龙井长叶茶树为试验材料,用酶联免疫法(ELISA)测定自然低温下茶树叶片内源激素含量的变化,以探讨自然低温下茶树内源激素变化规律。结果显示,自然越冬期间,茶树叶片中吲哚乙酸(IAA)含量的波动幅度最大,脱落酸(ABA)次之,而赤霉素(GA_3)与玉米素核苷(ZR)波动幅度较小;同时,除了ABA外,茶树其他内源激素IAA、ZR和GA_3含量变化趋势一致;激素间比值变化和相关性分析显示ZR与GA_3、ZR与IAA、IAA与GA_3含量变化极显著相关,ABA与IAA、ABA与ZR呈显著正相关。试验结果表明,茶树内源激素之间关系密切,茶树可能通过调控ABA/(GA_3+IAA+ZR)的比值来适应自然低温环境。