Mutation of the SP1 gene is responsible for the small-panicle trait in the rice cultivar Tachisuzuka,but not necessarily for high sugar content in the stem

Tachisuzuka, a rice cultivar grown for whole-crop silage, is characterized by the small-panicle trait and high-stem sugar content. To investigate the interrelationship between the two features, we attempted to identify the gene responsible for the small-panicle trait in Tachisuzuka, and also to examine the function of the gene using a knockout mutant line. A functionally disruptive deletion of the nucleotide sequence was found in the gene SP1 (Short-Panicle 1; Os11g0235200) in Tachisuzuka, which has been reported as a candidate gene for the small-panicle trait. A gene knockout mutant of SP1 obtained from the cultivar Nipponbare showed a small-panicle phenotype similar to that observed in Tachisuzuka. However, soluble sugar content in the stem did not increase in the knockout line, whereas starch content increased significantly. Overall, disruption of SP1 is responsible for the small-panicle phenotype of Tachisuzuka, but it is only partially associated with the high-stem sugar content.     

Gene Expression of Enzymes for Starch and Sucrose Metabolism and Transport in Leaf Sheaths of Rice (Oryza sativa L.) during the Heading Period in Relation to the Sink to Source Transition

Abstract

Leaf sheaths of rice plants are known to temporarily accumulate starch prior to heading, which is subsequently remobilized and transported into the panicle after heading. We investigated the time course for both carbohydrate content and steady state mRNA levels of enzymes related to starch and sucrose metabolism in the rice leaf sheath (Oryza sativa L. cv. Nipponbare). Leaf sheaths from the second leaf below the flag leaf accumulated high levels of starch before heading but they rapidly decreased after heading. In contrast, the flag leaf sheath did not accumulate as much starch. In the second leaf sheath, the mRNA levels of enzymes involved in starch synthesis, ADP glucose pyrophosphorylase (EC 2. 7. 7. 27), soluble starch synthase (EC 2. 4. 1.21) and branching enzyme (EC 2. 4. 1. 18) were high before heading, which coincided with rapid accumulation of starch. The mRNA levels of sucrose synthesis enzymes, cytosolic FBPase (EC 3. 1. 3. 11) and sucrose phosphate synthase (EC 2. 4. 1. 14), and the sucrose transporter (OsSUTI) increased at the time of heading, which was largely coincident with a decrease in the mRNA levels of starch synthesis enzymes. In the flag leaf sheaths, changes in mRNA levels of starch synthesis enzymes were not pronounced, however mRNA levels of sucrose synthesis enzymes and the sucrose transporter showed a clear increase throughout the heading period. The different characteristics observed between the two leaf sheaths will be discussed in relation to the sink to source transition.     

Evaluation of performance of sorghum varieties grown in Tokyo for sugar accumulation and its correlation with vacuolar invertase genes SbInv1 and SbInv2

ABSTRACT

The sugar-accumulating potential of global and local sweet and grain sorghum varieties were tested under the local conditions. The basis for this study was the dependency of sugar accumulation on temperature and photoperiod. Thus, the efficacy of cultivars as a bioenergy source would need to be determined based on their performance under the local environmental conditions. A strong correlation of sucrose content with brix was observed, enabling large-scale screening of varieties for high sucrose content. The morphological characteristics inherent in sweet sorghum, such as tall stems, greater number of leaves and a longer vegetative period, were found to correlate with the total stem sugar content. Assessment of sugars along the stem revealed maximum sugar accumulation in the upper intermediate to upper internodes in most of the varieties tested. The maximum theoretical ethanol yield (MTEY), a function of brix and juice yield, was determined as a better indicator of testing the performance of a variety as a potential source of bioethanol, mainly due to a negative correlation of stem juiciness and sucrose content in the varieties tested. Further, the relative expression of vacuolar invertase genes, SbINV1 and SbINV2, was studied, and a strong negative correlation of SbINV2 to stem sucrose content was observed. This reveals a possibility of involvement of vacuolar invertase gene, SbINV2, in sugar accumulation in sweet sorghum stems, and as a key candidate for molecular breeding studies for higher stem sugar content.     

Temporal and Spatial Variations of Carbohydrate Content in Rice Leaf Sheath and Their Varietal Differences

Abstract

In rice plant, carbohydrates accumulated in leaf sheaths before heading are translocated to grain and affect yield formation greatly. To clarify the intrinsic mechanism of carbohydrate metabolism in the leaf sheath, we investigated the temporal and spatial variations of carbohydrate metabolism in the third leaf sheath counted from the top and their varietal differences. The results revealed that the amount of carbohydrate decreased from the base to the tip of the leaf sheath, irrespective of variety and developmental stage. However, the proportion of starch content in the basal one-fifth of the leaf sheath to that in the whole sheath varied from 35% to 60% with the variety. Comparing the activities of enzymes related to starch metabolism at the base, middle and tip of the leaf sheath in IR65598-112-2 (New plant type) with those in Nipponbare, the activities of ADP-glucose pyrophosphorylase, branching enzyme and granule-bound starch synthase (GBSS) showed varietal differences. Particularly, the activity of GBSS may play an important role in the varietal difference in spatial variation of starch content in the leaf sheath. In IR65598-112-2, the sucrose content in the leaf sheath was extremely high, suggesting that sucrose may be one of the carbohydrate reserves in this line.     

不同播期下优质稻桂华占、八桂香花后碳氮物质流转与籽粒生长相关性

以桂华占、八桂香为材料,不同播期调控下,研究不同播期下优质稻花后植株碳氮流转与籽粒生长及品质的相关性.结果表明:(1)花后茎鞘、叶片干物质运转速度和运转率都与籽粒起始灌浆势呈正相关.籽粒活跃灌浆期、持续灌浆时间与花后茎鞘、叶片干物质运转速度和运转率呈极显著正相关.(2)播种期推迟不利于茎鞘碳同化物向穗部流转,茎鞘碳同化物转运对籽粒的产量和淀粉产量的贡献率表现为淀粉＞可溶性糖＞蔗糖,茎鞘碳同化物对籽粒产量及淀粉产量的贡献率远高于叶片.可溶性糖转运对籽粒产量和淀粉产量贡献率表现为SD1＞SD2＞SD3;蔗糖、淀粉对籽粒的产量贡献率表现为SD1＞SD2＞SD3.茎叶可溶性糖积累量的减少与籽粒直链淀粉含量和积累量增加是同步的,并且,茎叶可溶性糖积累量快速递减期(花后3～12 d)与直链淀粉含量和积累量快速递增期(花后6～12d)同步.(3)播种期推迟减少茎鞘和叶片总氮的积累,籽粒氮收获指数降低,但是播种期的推迟却增加茎鞘和叶片器官蛋白氮积累,有利于籽粒蛋白质含量提高.     

ABA对水分胁迫下水稻籽粒灌浆的调节

 利用水平分根系统研究了水稻抽穗后水分胁迫条件下ABA对水稻品种汕优63叶片光合特性、糖代谢和籽粒灌浆过程的调节。当一半根系受干旱胁迫时，叶片的水势和相对含量变化很小，但叶片和籽粒内ABA的含量显著增加。整个根系受干旱胁迫时，叶片的水势和相对含水量随着胁迫的增加而显著地降低，ABA含量则显著增加。半干和全干处理的水稻叶片的光合速率和RuBP羧化酶／氧化酶（Rubisco）的活性显著下降。叶片内蔗糖和淀粉的积累和代谢与叶片内ABA的含量和水分状况存在密切的关系，低浓度的ABA和高的叶水势与高的蔗糖积累和蔗糖磷酸合成酶活性相一致，但当叶片ABA的浓度增加时，即使叶片的水势与对照相似，叶片的蔗糖和淀粉积累以及蔗糖磷酸合成酶的活性则显著地下降，叶片的α－和β－淀粉酶活性似与ABA和水分状况关系不密切。ABA对籽粒灌浆有显著的抑制作用，ABA对籽粒灌浆的抑制作用至少部分与其对催化水稻籽粒内蔗糖代谢和淀粉积累的关键酶蔗糖合成酶的抑制有关。另外，干旱处理对叶片光合速率和蔗糖与淀粉积累的抑制程度显著高于半干旱处理，说明干旱本身也对这些过程有直接的效应。根据这些结果，作者认为，当水稻遇到干旱胁迫时，ABA对其光合作用、糖代谢以及籽粒的发育过程都有极其显著的调节作用。还就ABA对这些生理过程调节的可能性进行了讨论     

外源油菜素内酯缓解水稻穗分化期高温伤害的机理研究

【目的】明确水稻穗分化期高温下喷施2,4-表油菜素内酯(2,4-epibrassinolide, EBR)对穗生长及颖花形成的影响,并探究其生理机制。【方法】以热敏感型水稻IR36为材料,在幼穗分化期设置40℃高温和32℃适温两个处理,并喷施EBR,研究幼穗碳水化合物供应、蔗糖代谢、细胞分裂素代谢及抗氧化能力的变化。【结果】1)高温和适温喷施EBR,水稻每穗粒数分别比不喷施的对照增加13.7%和45.7%,其中以喷施0.15 mg/L效果最好,缓解了高温对水稻幼穗生长的抑制,增加颖花分化数和降低颖花退化率。2)喷施EBR对叶片净光合速率无显著影响,但促进幼穗中干物质和非结构性碳水化合物积累。EBR喷施增加高温下幼穗中蔗糖转运基因OsSUT1、OsSUT2和OsSUT4的表达,并显著提高蔗糖代谢相关酶活性,EBR对高温下碳水化合物利用的促进作用大于适温处理。3)喷施EBR降低高温下细胞分裂素氧化酶基因OsCKX5和OsCKX9的表达量,同时促进细胞分裂素合成和信号调节相关基因的表达,并在适温下也表现出类似的效应。4)喷施EBR降低高温下超氧阴离子含量,增强了超氧化物歧化酶、过氧化氢酶和过氧化物酶活性。【结论】高温下,喷施适宜浓度的EBR促进碳水化合物向幼穗的转运,抑制细胞分裂素分解,同时降低高温引起的过氧化伤害,进而缓解了高温对颖花形成的伤害。适温条件喷施EBR也对颖花形成具有一定的促进作用。     

外源油菜素内酯缓解水稻穗分化期高温伤害的机理研究

【目的】明确水稻穗分化期高温下喷施2,4-表油菜素内酯(2,4-epibrassinolide, EBR)对穗生长及颖花形成的影响，并探究其生理机制。【方法】以热敏感型水稻IR36为材料，在幼穗分化期设置40℃高温和32℃适温两个处理，并喷施EBR，研究幼穗碳水化合物供应、蔗糖代谢、细胞分裂素代谢及抗氧化能力的变化。【结果】1)高温和适温喷施EBR，水稻每穗粒数分别比不喷施的对照增加13.7% 和45.7%，其中以喷施0.15 mg/L效果最好，缓解了高温对水稻幼穗生长的抑制，增加颖花分化数和降低颖花退化率。2)喷施EBR对叶片净光合速率无显著影响，但促进幼穗中干物质和非结构性碳水化合物积累。EBR喷施增加高温下幼穗中蔗糖转运基因OsSUT1、OsSUT2和OsSUT4的表达，并显著提高蔗糖代谢相关酶活性，EBR对高温下碳水化合物利用的促进作用大于适温处理。3)喷施EBR降低高温下细胞分裂素氧化酶基因OsCKX5和OsCKX9的表达量，同时促进细胞分裂素合成和信号调节相关基因的表达，并在适温下也表现出类似的效应。4)喷施EBR降低高温下超氧阴离子含量，增强了超氧化物歧化酶、过氧化氢酶和过氧化物酶活性。【结论】高温下，喷施适宜浓度的EBR促进碳水化合物向幼穗的转运，抑制细胞分裂素分解，同时降低高温引起的过氧化伤害，进而缓解了高温对颖花形成的伤害。适温条件喷施EBR也对颖花形成具有一定的促进作用。     

施钙对间作遮荫条件下花生生育后期光合特性、糖代谢及产量的影响

于2016-2017年以花育25号为材料,在花生单作和间作条件下,设置施钙和不施钙处理,研究钙肥对单作花生、间作中间行和间作边行花生的植株性状、功能叶生育后期光合特性、糖代谢酶活性及产量的影响。结果表明,施用钙肥降低了花生主茎高和侧枝长,增加了花生分枝数、主茎节数,提高了叶片叶绿素含量、光合速率、蔗糖含量及蔗糖代谢相关酶活性;单作和间作花生荚果产量平均增产397.2 kg/hm^2,平均增产率19.9%。相同施钙水平下,越靠近玉米行的间作边行花生受遮荫影响越大,其主茎高、侧枝长较大,蔗糖合成酶(SS)、蔗糖磷酸合成酶(SPS)活性等生理指标低于单作花生。与单作不施钙比较,施钙显著增加了间作花生叶绿素含量,使其光合特性、蔗糖含量、SS、SPS酶活性无显著降低,降低了间作花生的减产幅度。本试验条件下,每公顷施用钙肥300kg可部分缓解间作遮荫对花生的不利影响。     

甘蔗蔗糖转运蛋白ShSUT4基因克隆及表达分析

采用RACE技术从甘蔗体内克隆出一个新型蔗糖转运蛋白基因,命名为ShSUT4（GenBank登录号为GQ485583.1）,预测其编码501个氨基酸,存在GPH（蔗糖/H+共转运体）超家族保守结构域,具有12跨膜结构。初步研究结果表明,ShSUT4在甘蔗根茎叶中均有表达;且在9个不同甘蔗品种成熟茎中表达量存在差异,在其中8个品种中ShSUT4表达量的高低与所测茎节中锤度高低呈正相关性,推测ShSUT4可能参与调控甘蔗体内蔗糖的积累。     

杂交水稻始穗期氮钾营养对剑叶生理特性的影响

 采用盆栽试验研究了杂交水稻汕优63在施基肥的基础上，始穗期供给 NK营养对剑叶生理特性的影响。施用NK，可促进剑叶叶绿素含量、光合速率、蔗糖磷酸合成酶(SPS)、过氧化物酶(POX)、超氧物歧化酶(SOD)、硝酸还原酶(NR)活性提高，呼吸速率下降，增加剑叶的可溶性糖和可溶性蛋白含量及根系活力，加速14C同化物从剑叶的输出，提高14C同化物在稻穗的分布积累及输入积(IAP)。讨论了始穗期共施NK营养提高结实率、谷粒充实度及稻谷产量的良好效果     

The Effect of the Amount of Nitrogen Fertilizer on Starch Metabolism in Leaf Sheath of Japonica and Indica Rice Varieties during the Heading Period

Abstract

The effects of the amount of nitrogen fertilizer on the starch metabolism of rice leaf sheath during the heading period in the japonica rice variety, cv. Nipponbare were compared with those in the indica varieties, cv. Tetep and Johna. The rice plants were grown under a low- (similar to the standard nitrogen level in paddy field) or high-nitrogen condition, and the starch content of the second leaf sheaths below the flag leaf was analyzed from the second leaf stage (growth stage 1) until 21 days after the heading (growth stage 7). The starch content of the plants grown under the high-nitrogen condition at the heading stage (growth stage 4) was lower than that under a low-nitrogen condition in all the varieties. The decrease in the activity of starch branching enzyme (SBE) was considered to be important for the repression of starch accumulation under a high-nitrogen condition. Under the high-nitrogen condition, Nipponbare accumulated more starch in the second leaf sheath than indica varieties at the heading stage. However, the phenomenon could not be accounted for by the activities of AGPase and SBE. Semi-quantitative RT-PCR analysis suggested that the lower activities of SBE in the second leaf sheath under the high-nitrogen condition may be due to, at least in part, the decrease in the expression level of RBE4.     

不同氮素吸收类型粳稻品种吸氮能力的差异及原因分析

 2008-2009年,在群体水培条件下,以国内外不同年代育成的94个常规粳稻品种为供试材料,测定植株各器官干物质量和含氮率、产量及其构成因素等,采用组内最小平方和的动态聚类方法将供试品种按吸氮量的大小从低到高依次分为A、B、C、D、E、F 等6类,以探明影响氮素高效吸收型粳稻品种吸氮能力的主要原因。结果吸收型品种抽穗前后吸氮量显著大于氮素低效吸收型品种,抽穗前吸氮量对总吸氮量影响显著大于抽穗后吸氮量;3）氮素高效吸收型品种单穗吸氮量显著大于氮素低效吸收型品种,但单位面积穗数无优势,单穗吸氮量对总吸氮量的影响显著大于单位面积穗数;4）氮素高效吸收型品种播抽历期、全生育期较长,群体与个体吸氮强度大,吸氮强度对吸氮量的影响显著大于生育期;5）氮素高效吸收型品种干物质生产量显著大于氮素低效吸收型品种,但植株含氮率无优势,干物质生产量对总吸氮量的影响显著大于植株含氮率,干物质生产量大是氮素高效吸收型品种吸氮能力强的一个重要因素;6）氮素高效吸收型品种各器官（根、茎鞘叶、穗）吸氮量均显著大于氮素低效吸收型品种,抽穗前茎鞘叶吸氮量大,抽穗后氮从茎鞘叶向穗部转移多,成熟期穗部吸氮量大,有利于提高氮高效吸收型品种氮素累积量。表明：1）供试品种间吸氮量的差异很大,总吸氮量最大品种为最小品种的2.44倍,氮素高效吸收型品种平均产量极显著高于氮素低效吸收型品种;2）氮素高效     

Recurrent selection for sucrose content has altered growth and sugar accumulation in sugarcane

Sucrose content is one of the main factors sugarcane (Saccharum spp. hybrids) breeders use in selecting new cultivars. To determine how growth and sugar content have been altered by six cycles of recurrent selection for sucrose, five cultivars from the first generation (released from 1924 to 1933) were compared with five cultivars from the seventh generation (released from 2003 to 2007). In July of 2006 and 2007, we flagged 20 stalks per plot and marked the top internode that was just beginning to elongate. We then sampled one stalk per plot at weekly to biweekly intervals for 12 weeks. We measured stalk length and internode number, and the length, fresh weight, dry weight, water content, and sugar content of the marked internode. Stalks from the Generation 7 cultivars were taller, and had more internodes than those from Generation 1 cultivars. The marked internodes of Generation 7 and Generation 1 cultivars had similar elongation rates during early development, but elongation ended earlier in Generation 7 cultivars so that internodes of Generation 7 cultivars were shorter when fully elongated than those of Generation 1 cultivars. These shorter internodes had lower fresh weights, but similar dry weights as the longer Generation 1 internodes. Water content also decreased faster in Generation 7 than Generation 1 internodes. Generation 7 internodes had more total sugar and more sucrose throughout development. Generation 7 internodes also maintained a higher sucrose:total sugar ratio until the end of the sampling period. We conclude that recurrent selection for sucrose content in sugarcane has altered the allocation of photosynthate from growth to storage within the internode. This is possibly due to a change in the regulation of sucrose metabolism within the internode.     

高、低糖甘蔗品种苗期糖分含量及代谢相关酶活性分析

以高糖(GT35)和低糖(B8)甘蔗品种苗期不同部位的叶和茎为材料,采用HPLC技术测定蔗糖、葡萄糖和果糖含量,分析2个甘蔗品种叶和茎中蔗糖代谢相关酶活性与糖分含量的相关性和差异性。结果表明:2个甘蔗品种苗期叶中蔗糖含量与SPS和SS-s酶活性呈显著正相关,茎中己糖含量与NI酶活性呈显著正相关,茎中蔗糖含量与SPS酶活性呈显著正相关,而与SS-c、SAI和CIN酶活性呈显著负相关。GT35茎中蔗糖含量显著高于B8,叶中蔗糖含量显著低于B8。GT35茎中SPS和叶中SS-s酶活性均显著高于B8,茎中SS-s和SS-c酶活性低于B8,其中只有幼茎中SS-c酶活性与B8差异不显著。说明苗期叶中高SS-s酶活性,茎中高SPS酶活性,低SS-s和SS-c酶活性,可能是调节高糖甘蔗品种苗期茎中蔗糖积累的重要因素。     

叶肉细胞特异表达焦磷酸化酶基因OsIP1在不同源库类型水稻品种中的效应

 将水稻自身焦磷酸化酶基因OsIP1置于叶肉细胞特异表达启动子下,利用农杆菌介导法将嵌合基因cyFBPase:OsIP1分别导入“源限制型” 水稻品种中超123和“库限制型” 品种农垦57。 根据荧光定量PCR结果和农艺性状,筛选高表达且农艺性状没有明显改变的T2转基因纯合株系,用以检测和分析在水稻叶肉细胞中特异性过表达水稻焦磷酸化酶基因的效应。初步的研究结果显示：1）在营养生长期,转基因株系的最高茎蘖数和穗数比各受体亲本均有不同程度的提高,尤其是在分蘖性较强的品种上;2）在籽粒灌浆结实期,叶片、叶鞘中可溶性总糖、蔗糖和淀粉含量在整个灌浆期的变化趋势与对照相似,且多数转基因植株叶片和叶鞘中的蔗糖含量（除了灌浆高峰期时的叶鞘）均显著高于对照;3）转基因株系单株干物质量较野生型对照有显著提高。单株产量呈现不同程度的增加,其中“源限制型”品种中超123转基因株系单株产量较对照增幅达显著水平。     

耕作方式和施氮量对旱地冬小麦开花后干物质转运特征、糖含量及产量的影响

为探讨耕作方式和氮肥对旱地小麦的互作效应,在甘肃半干旱雨养农业区大田试验条件下,采用双因素裂区设计,以常规耕作(CT)、秸秆还田(CTI)、全膜覆土穴播(PM)、免耕秸秆覆盖(NTS)4种耕作方式为主区,75、150、225、300kg·hm~(-2)4个施氮量(分别用N1～N4表示)为副区,分析了不同耕作方式及施氮量组合处理下旱地冬小麦花后干物质转运、糖含量及产量的差异。结果表明,4种耕作方式中,PM的株高最高,叶面积最大,籽粒产量最高,较CT增产14.50%。PM增产主要是通过增加穗长和穗粒数来实现,也归因于花前营养器官干物质的积累量及其在花后向籽粒中转运量、转运效率和对籽粒产量的贡献率较CT显著增加,特别是增加了叶片和颖壳的干物质转运量、转运效率。CTI的千粒重和有效穗数虽然最高,但产量与CT无显著差异;NTS的株高、千粒重、有效穗数、干物质积累量和花后向籽粒中转运量均处于较低水平,产量较CT降低16.74%。施氮显著增加了旱地冬小麦的籽粒产量,平均产量表现为N4N2N3N1。CT、CTI、NTS下,施氮的增产作用显著,但PM下不显著。在所有处理中,PMN2的籽粒产量最高,比最低的NTSN1增加70.55%。施氮增产的原因主要是促进了不同器官干物质积累和开花后干物质转运。NTS提高了各器官的可溶性糖含量,但其效应在不同生育时期存在差异,茎秆主要表现在开花后20～30d,叶片和颖壳在开花后10～40d,叶鞘在开花后20～40d,籽粒在开花后10～30d。施氮显著降低了开花后0～30d茎秆和叶片的可溶性糖和蔗糖含量,但显著增加了开花后20d籽粒的可溶性糖含量。以上结果说明,在甘肃旱地雨养农业区,常规耕作、秸秆还田、全膜覆土穴播下冬小麦高产的氮肥施用量以中等水平(150kg·hm~(-2))最佳,免耕秸秆覆盖下需增加氮肥施用量(300kg·hm~(-2))。     

花生籽仁蔗糖含量多世代联合群体主基因+多基因遗传模型分析

花生是重要的油料和经济作物,在世界范围内广泛种植.甜味是与花生口感及风味高度相关的遗传性状,花生的甜味主要来源于花生籽仁中的蔗糖,蔗糖含量达到6％以上时,其口感及风味较好.因此,提高花生籽仁的蔗糖含量是改善花生口感及风味的关键因素之一.但迄今为止,对花生籽仁蔗糖含量的遗传分析未见报道.本研究以2组高、低花生籽仁蔗糖含量...     

Gene Expression and Accumulation of Rubisco in Bundle Sheath and Mesophyll Cells during Leaf Development and Senescence in Rice,a C3 Plant

Abstract

Gene expression of ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco) large subunit (rbcL) and small subunit (rbcS) in bundle sheath and mesophyll cells of rice, a C₃ plant, was examined during leaf development and senescence by in situ hybridization. Localization of Rubisco protein in both cells was also examined by immuno-electron microscopy. Gene expression and accumulation of Rubisco were related with the chlorophyll fluorescence parameters. The chlorophyll fluorescence parameters, such as F_v/F_m and Φ_psii, gradually increased during leaf development with the increase in the accumulation of Rubisco. However, the chlorophyll fluorescence parameters decreased earlier than the Rubisco content during leaf senescence. The expression of rbcS decreased earlier in bundle sheath cells than in mesophyll cells during leaf development, whereas the expression of rbcL in both cells was retained during leaf development and decreased during leaf senescence. On the other hand, Rubisco content of bundle sheath and mesophyll cells increased during leaf development and decreased during leaf senescence. Rubisco was retained even after the disappearance of the expression of rbcS and rbcL detectable by in situ hybridization. The present results suggest that the expression pattern of rbcS in bundle sheath cells was somewhat different from that in mesophyll cells, but this difference was not reflected in Rubisco content.