小麦不同品种光合速率和~(14)C同化物分配对源库比改变的响应

选用千粒重大小不同的小麦品种,研究了去除顶端两个小穗对两类品种（大粒品种和小粒品种）穗部性状、籽粒平均灌浆速率、单穗平均增重速率、植株光合速率及１４Ｃ同化物运输分配的影响。试验结果表明,去除顶端两个小穗后,两类品种的籽粒平均灌浆速率和单穗平均增重速率（分别表征籽粒库容活性和穗粒库容活性）相应提高,穗粒重表现为补偿性增长。两类品种比较,小粒品种的增长幅度大于大粒品种。穗粒库容活性增强使得小粒品种灌浆中后期的植株光合速率提高,使两类品种分配到籽粒中的１４Ｃ同化物比例增加。从而表明,无论是植株光合速率还是同化物的运转分配皆受库容活性的调控,调控方式和幅度因品种类型而不同。     

源库关系改变对小麦灌浆期植株光合速率及~(14)C同化物运转分配的影响

选用千粒重大小不同的小麦品种,研究了去除顶端两个小穗对两类品种（大粒品种和小粒品种）千粒重、穗粒数、穗粒重、籽粒平均灌浆速率、单穗平均增重速率、植株光合速率及１４Ｃ同化物运转分配的影响。试验结果表明,去除顶端两个小穗后,两类品种的千粒重提高,穗粒数降低或基本不受影响,但降低比例明显低于去除小穗数的比例。籽粒平均灌浆速率和单穗平均增重速率（分别表征籽粒库容活性和穗粒库容活性）相应提高。结果,两类品种的穗粒重表现为补偿性增长。两类品种比较,小粒品种的增长幅度大于大粒品种。穗粒库容活性增强使得小粒品种灌浆中后期的植株光合速率提高,使两类品种分配到籽粒中的１４Ｃ同化物比例增加。从而表明,无论是植株光合速率还是同化物的运转分配皆受穗粒库容活性的调控,调控方式和幅度因品种类型而不同。但提高其穗粒重的着眼点都应当是提高穗粒库容活性。     

小麦不同品种光合速率和^14C同化物分配对源库比改变的响应

选用千粒重大小不同的小麦品种,研究了去除顶端两个小穗对两类品种（大粒品种和小粒品种）穗部性状,粒粒平均灌浆速率,单穗平均增重速率,植株光合速率及＾１４Ｃ同位物运输分配的影响。试验结果表明,去除顶端两个小穗后,两类品种的籽粒平均灌浆速率和单穗平均增重速率（分别表征籽粒库容活性和穗粒库容活性）相应提高,穗粒重表现为补偿性增长。两类品种比较,小粒品种的增长幅度大于大粒品种。穗粒库容活性增强使得小粒品种灌     

源库关系改变对小麦灌浆期植株光合速率及^14C同化物运转分配 …

选用千粒重大小不同的小麦品种,研究了去除顶端两个小穗对两类品种千粒穗、穗粒数、穗粒重、籽粒平均灌浆速率、单穗平均增重速率、植株光合速率及＾１４Ｃ同化物运转分配的影响。     

大小粒型藜麦籽粒表型、灌浆特性及淀粉合成酶活性的差异分析

【目的】籽粒大小是影响藜麦产量、商品性和加工特性的重要因素,考察灌浆期大小粒型藜麦籽粒表型、灌浆特性和淀粉合成酶活性的差异,为大粒型藜麦品种的选育提供理论指导。【方法】选择千粒重大于5.0 g和小于3.0 g的藜麦材料各两份,在青海省农林科学院种质资源创新试验基地进行田间试验,比较自灌浆期始7 d、14 d、21 d和28 d籽粒表型、灌浆特性和淀粉合成酶活性等在大小粒型藜麦间的差异。【结果】（1）大小粒型藜麦籽粒面积、周长、直径、粒长、粒宽表型性状随着生育时期均极显著增大,且粒型间存在显著差异,并以籽粒面积和周长差异最大,大粒型藜麦显著高于小粒型藜麦9.12%~11.54%和21.49~23.92%。（2）灌浆期间大粒型藜麦百粒干重始终显著高于同期小粒型藜麦,平均增幅在21.23%～31.04%;大小粒型藜麦灌浆速率随生育期均先上升后下降,均符合“慢-快-慢”的变化规律,但达到峰值时间和峰高明显不同,大粒型峰值出现早而高,小粒型则低而迟。（3）淀粉分支酶（SBE）、蔗糖合成酶（SS）、可溶性淀粉合成酶（SSS）和ADPG焦磷酸化酶（AGP）在大小粒型藜麦籽粒灌浆期呈现不同的变化趋势,SBE和SS活性表现为小粒型藜麦强于大粒型藜麦,而SSS和AGP活性则表现为大粒型藜麦强于小粒型藜麦。【结论】藜麦籽粒灌浆期间4种淀粉合成酶活性的差异,致使淀粉合成积累量和灌浆速率峰值的不同,进而形成籽粒表型性状的差异,而SSS和AGPase是影响藜麦籽粒大小形成的关键酶。     

不同粒型小麦品种内源GA3和ABA含量变化及其与源库的关系

小麦大粒品种籽粒和旗叶中的GA3 含量高于小粒品种 ,而ABA含量低于小粒品种 ,其变化均为单峰曲线 ;但大粒品种籽粒和旗叶中的GA3 的峰值高于小粒品种 ,而ABA的峰值均低于小粒品种 ,而且大粒品种籽粒中ABA出现峰值的时间比小粒品种晚。大粒品种旗叶中GA3 /ABA与光合速率呈显著正相关 (r =0 .884 0 ) ,籽粒中GA3 /ABA与籽粒灌浆速率呈显著正相关 (r =0 .90 70 ) ,籽粒与旗叶中的GA3 /ABA相关不显著 ,而小粒品种籽粒与旗叶中的GA3 /ABA相关达极显著水平 (r =0 .95 98 )     

小麦花后水分亏缺和复水对同化物转运和籽粒灌浆的影响

为了阐明水分亏缺对小麦花后同化物转运和籽粒灌浆的影响及其生理机制的相关变化,以盆栽小麦旱作品种‘长旱58’为材料,自花后9 d起,设置正常供水(WW)、中度干旱胁迫后复水(MD)和重度干旱胁迫后复水 (SD)3个水分处理,比较干旱胁迫后复水处理对小麦籽粒产量、产量构成因素及水分利用效率、强弱势粒灌浆动态、旗叶光合性能、茎鞘非结构性碳水化合物(NSC)转运、籽粒形成关键酶活性变化等的影响。结果表明：(1)与WW相比,MD处理显著增加了小麦穗粒数和千粒重,进而提高籽粒产量、水分利用效率和小麦弱势粒的最大灌浆速率和平均灌浆速率,对强势粒则无显著影响,而SD处理则显著降低了穗粒数、千粒重、强弱势粒的最大灌浆速率和平均灌浆速率,但水分利用效率显著高于WW处理。(2)MD处理植株旗叶在小麦灌浆过程中维持了与WW基本相同的净光合速率,同时在小麦花后9~20 d时MD处理下气孔导度和蒸腾速率变化不明显,而在SD处理下气孔导度和蒸腾速率则急剧下降;另外,与WW相比,在整个灌浆期MD处理下旗叶叶绿素含量变化不显著,而SD处理下叶绿素含量呈大幅下降趋势。(3)MD处理提高了小麦弱势粒蔗糖合成酶和腺苷二磷酸葡萄糖焦磷酸化酶活性;同时使灌浆中后期有较高的果聚糖水解酶(FEH)活性和较低果聚糖含量,显著增强了茎鞘同化物质转运,提高茎鞘储藏物质对粒重的贡献率。研究发现,中度水分胁迫后复水处理小麦植株具有较好的叶片性能、花后较多的茎鞘同化物向籽粒转运以及较高的弱势粒库活性,从而提高旱作小麦弱势粒灌浆速率,增加穗粒数和粒重, 进而提高籽粒产量。     

潘庆民1,于振文2,王月福2

采用盆栽和水泥池栽研究了追氮时期对小麦光合作用、14C同化物运转分配和硝酸还原酶(NR)活性的影响.结果表明,拔节(雌雄蕊原基形成)期较起身(二棱)期追施氮肥,显著提高了小麦开花后的旗叶叶绿素含量和单叶光合速率;灌浆期旗叶14C同化物向籽粒转移比例显著提高,而在营养器官的滞留比例显著降低;旗叶和根系中硝酸还原酶(NR)活性亦显著提高.小麦穗粒数、粒重和产量增加,蛋白质含量提高.     

追氮时期对小麦光合作用、^14C同化物运转分配和硝酸还原酶活性的影响

采用盆栽和水泥池栽研究了追氮时期对小麦光合作用、^14C同化物运转分配和硝酸还原酶（NR）活性的影响,结果表明,拔节（雌雄蕊原基形成）期较起身（二棱）期追施氮肥,显著提高了小麦开花后的旗叶叶绿素含量和单叶光合速率;灌浆期旗叶^14C同化物向籽粒转移比例显著提高,而在营养器官的滞留比例显著降低;旗叶和根系中硝酸还原酶（NR）活性亦显著提高,小麦穗粒数、粒重和产量增加,蛋白质含量提高。     

疏剪不同穗位小穗对小麦籽粒结实和粒重的影响

１９９７～１９９８年在河南省农作物品种展览中心以中大穗小麦品种温麦６号为材料,设计了去除不同穗位小穗的试验。结果表明,去除不同位小穗对结实粒数和粒重的影响不同, 除顶端小穗的粒数下降较多,穗粒重最低,却除基部小重申对结实粒数和粒重的影响较小,穗粒数和粒重下降较少;却除中部小穗对结实粒数影响较大,穗粒数量小,其穗粒重因剩余籽粒单粒重增加而得以一定程度补偿。     

Effect of awns and drought on the supply of photosynthate and its distribution within wheat ears

The presence of awns doubled the net photosynthetic rate of wheat ears and also increased the proportion of ¹⁴CO₂ assimilated by the ear that moved to the grain. The effect of water supply on photosynthesis and movement of assimilates was greater for leaves than ears, so that drought increased the proportion of assimilate contributed by ear photosynthesis to grain filling from 13% to 24% in the awnless ears, and from 34% to 43% in the awned ears. ¹⁴C assimilated by the ears was most important to the economy of the upper spikelets and to the distal florets in each spikelet, whereas flag leaf assimilate went mainly to the spikelets in the lower half of the ear, and to the proximal florets. Awns increased grain yield in the dry but not in the irrigated treatment, despite the large contribution of awned ears to grain filling. Either the supply of assimilate did not limit grain yield when water supply was not limiting, or there were compensating disadvantages to awns. However, they did not seem to have any adverse effect on the development of the upper florets, nor did they reduce grain number per ear.     

Ethylene control of seed coat development in low and high sterile semidwarf indica rice cultivars

Although basally positioned inferior spikelets of rice panicles emerge late from the flag leaf enclosure (boot), they mature early which precludes adequate grain filling. It is assumed that extended exposure to ethylene inside the boot restricts assimilate partitioning to the endosperm in basal spikelets by affecting the functions of seed coat. In the present study, ethylene concentration inside the boot was measured in two high yielding rice cultivars differing in percentage of spikelet sterility. To manipulate the concentration/action of ethylene, silver nitrate, aminoethoxyvinyl glycine and 2-chloroethylphosphonic acid were injected into the boot. The effect of these chemicals on the concentration of photosynthetic pigments, lipid peroxidation and peroxidase activity of the seed coat and lemma and palea were measured to monitor development. Ethylene reduced development during the juvenile phase but accelerated degradation of the photosynthetic tissues of the spikelets in the senescent phase. Boot ethylene correlated positively with number of barren spikelets in the panicle and negatively with concentration of photosynthetic pigments of the seed coat of inferior spikelets. The concentration of ethylene was higher in the high sterile cultivar Mahalaxmi than that of the low sterile Mahanadi. Inhibition of ethylene action or synthesis improved grain filling. The chemicals were most effective on the inferior spikelets. It was concluded that ethylene retarded seed coat development during the prestorage phase and reduced grain filling of basal spikelets.     

Apoplasmic assimilates and grain growth of contrasting rice cultivars differing in grain dry mass and size

Apical dominance in assimilate filling impacts grain growth in basal spikelets of rice panicle. In this study, organic materials of the pericarp, apoplasmic space and endosperm of the apical and basal caryopses, and photosynthesis of the flag leaf were measured during early part of grain development in three types of rice cultivars with similar phenology, but difference in grain weight and size in the dry and wet seasons of 2006 and 2007, respectively. Photosynthetic activity of the flag leaf was consistently low in small-seeded cultivars. Rates of grain filling and cell division of endosperm and concentration of assimilates, starch, proteins and chlorophylls of the caryopsis were lower, but spikelet ethylene production and peroxidase activity were higher in a small-seeded cultivar compared to a big-seeded cultivar. Similar disparities in grain filling and other attributes were noticed for the inferior basal spikelets of the panicle compared to the superior apical spikelets, except the assimilate concentration of the pericarp and endosperm. Temporal fluctuation in assimilate concentration of the organs were similar between the cultivars. Concentration of apoplasmic assimilates mostly exhibited negative correlation with that of pericarp and endosperm. Compared to the apical spikelets, correlation was more negative for the basal spikelets. Conversely, correlation was positive between the concentration of apoplasmic assimilates and endosperm cell number and grain weight of the cultivars. Ethylene released from the spikelets at anthesis affected growth and cell division rates of endosperm and enhanced protein and chlorophyll degradation and peroxidase activity of the caryopsis. It was concluded that variation in spikelet ethylene production may be responsible for differences in size or weight of grains among rice cultivars and spikelets at different locations of the panicle. The concentration of apoplasmic assimilates could be an indicator for grain filling capacity, and ethylene regulated the concentration by affecting pericarp activity for assimilate unloading.     

重穗型杂交水稻籽粒灌浆过程中强势和弱势颖花内源IAA、ABA和GA水平的动态状况

研究了重穗型杂交水稻培矮 6 4s/E3 2的灌浆过程和强、弱势颖花中内源IAA、ABA和GA1 GA3水平的动态状况。籽粒发育过程中不同内源激素水平高低依次为 :IAA >GA1 GA3>ABA。IAA和ABA水平在强势颖花中较高而GA1 GA3水平在弱势颖花中较高。 3种激素水平的变化与谷粒增重速率之间均存在正相关 ,两个最高的相关系数值分别存在于单位鲜重样本的IAA含量(ng/gFW ) 与籽粒鲜重的增重速率之间 (r =0 .82 1 8 )和单个籽粒IAA含量 (ng/grain)与籽粒干重的增重速率之间 (r =0 .8485 )。推测启动和维持籽粒灌浆过程可能需要较高的IAA水平 ;ABA可能具有促进籽粒中同化物的累积和种子成熟的作用 ;GA1 GA3可能具有保持弱势颖花活性的特殊作用     

Effect of Source-to-sink Ratio on Partitioning of Dry Matter and14C-photoassimilates in Wheat during Grain Filling

Increasingly, wheat (Triticum aestivumL.) is being grown intropical environments, but there is inadequate information aboutthe physiological processes limiting yield. In this investigation,the source:sink ratio was manipulated to examine the performanceof source-sink interactions after anthesis and the factor(s)limiting grain filling in tropical conditions. Plants of threewheat cultivars, Cuba C-204, Candeias and IAC-60, were artificiallymodified to give different source:sink ratios. The treatmentswere: I, Control; II, all spikelets on one side of the spikeremoved; III, all spikelets removed except the four centralspikelets of the spike; and IV, flag leaf blade removed. Thedistribution of dry matter between kernels and stem internodeswas analysed at harvest in all three cultivars. Partitioningof¹⁴C-photoassimilates was measured on three occasions afteranthesis in the cultivar Cuba C-204. Modifications of source:sinkratio led to different patterns of allocation of dry matterbetween cultivars and sowing dates. The reduction in sink sizein treatment II produced no significant change in the mass pergrain in the January sowing, but this was enhanced in two cultivarsin the November sowing. In treatment III, both mass per grainand translocation of¹⁴C-photoassimilates declined, apparentlydue to feedback inhibition of photosynthesis. The participationof stem reserves in grain filling and the existence of genotypicdifferences in response to availability of photoassimilateswere corroborated. The pattern of partitioning of dry matterobserved in plants in this investigation suggests a source limitation,particularly during the November sowing. This pattern differedmarkedly from that in other studies, most of which have beenmade in temperate areas.Copyright 1999 Annals of Botany Company Photoassimilates, sink, source, partitioning, grain filling, wheat.     

重穗型杂交水稻籽粒灌浆过程中强势和强势颖花内源IAA、ABA和GA水平的动态状况

研究了重穗型杂交水稻培矮 6 4s/E3 2的灌浆过程和强、弱势颖花中内源IAA、ABA和GA1 GA3水平的动态状况。籽粒发育过程中不同内源激素水平高低依次为 :IAA >GA1 GA3>ABA。IAA和ABA水平在强势颖花中较高而GA1 GA3水平在弱势颖花中较高。 3种激素水平的变化与谷粒增重速率之间均存在正相关 ,两个最高的相关系数值分别存在于单位鲜重样本的IAA含量(ng/gFW ) 与籽粒鲜重的增重速率之间 (r =0 .82 1 8 )和单个籽粒IAA含量 (ng/grain)与籽粒干重的增重速率之间 (r =0 .8485 )。推测启动和维持籽粒灌浆过程可能需要较高的IAA水平 ;ABA可能具有促进籽粒中同化物的累积和种子成熟的作用 ;GA1 GA3可能具有保持弱势颖花活性的特殊作用     

氮肥对不同海拔地区种植的水稻开花前后饲喂的~(14)C最终分配的影响

本文对不同海拔地区不同施肥方式(基肥/穗肥比例)下种植的水稻于开花前后饲喂的~(14)C最终在营养体和米及谷壳中的分配比例作了比较,表明不同海拔地区和不同施肥方式造成的孕穗期饲喂的~(14)C最终在营养体的百分数取决于营养体大小(r=0.9449);灌浆期饲喂的~(14)C最终在米中分配的百分数取决于库/源比(r=0.9503)。     

Source-sink manipulation effects on postanthesis photosynthesis and grain setting on spike in winter wheat

Source-sink manipulation could regulate the net photosynthetic rate (PN) of winter wheat after anthesis, however, the direction and magnitude of the regulation varied with time after anthesis. The PN was significantly increased by source reduction at the initial time of grain filling, but sink reduction had little influence on the PN, which suggested that the sink (spike) limitation did not occur at this time. Source-sink relation markedly affected PN during rapid grain filling. The PN was increased by source reduction and decreased by sink reduction significantly, which indicated that PN was closely associated with the change of source or sink size. The effect of source-sink manipulation on PN had some relationship with the occurrence of plant senescence at the time of late grain filling. Source reduction accelerated the senescence and dropped the PN, meanwhile, sink reduction delayed the senescence and promoted the PN. A direct relation between the effect of source-sink manipulation on PN and stomatal limitation was not found. Removing one quarter of leaves (RQ) had little influence on spike development after anthesis. In this case there was enough compensation in source production through photosynthesis. Removing one half of leaves (RH) made grain mass per spike and mass of grains lowered, especially the grain mass in the top and base positions of spike declined markedly. The source supply was grain-limiting. Removing one quarter of spikelets (RS) was beneficial to grain-setting in the remaining spikelets, leading to the increase of grain mass. Thus promoting the source supply of photosynthates after anthesis is of major importance for grain to set and to develop.