Fine mapping and cloning of MT1,a novel allele of D10

Rice tillering is an important determinant for grain production.To investigate the mechanism of tillering,we characterized a multiple tillering mutant (mt1) identified from the japonica variety,Zhonghua 11,treated with EMS.This mutant exhibits advanced tillering development and dwarfed compared with wild-type plants.Genetic analysis and fine gene mapping indicated that the mt1 mutant was controlled by a recessive gene,residing on a 29-kb window on AP003376 of chromosome 1.One putative gene in this region,encoding a carotenoid cleavage dioxygenase 8 (CCD8),was allelic to D10.The mt1 mutant phenotype was complemented by introduction of wild-type MT1,and knockdown of MT1 in wild-type rice mimicked the mutant phenotype.Real-time PCR analysis indicated that the MT1 gene is expressed highly in stems and at a low level in axillary buds,panicles,leaves,and roots.In addition,MT1 expression is clearly under feedback regulation.     

水分胁迫对B优827生理特性和产量性状的影响

对籼型杂交水稻B优827和中度抗旱品种冈优725（对照）分蘖期进行了正常水分条件（相对含水量100％,V/V）、轻度水分胁迫（相对含水量70％,V／V）、重度水分胁迫（相对含水量50％,V／V）的水分胁迫处理9d,研究了光合速率、超氧离子（O2-）、抗氧化酶（SOD、CAT）活性等生理特性和产量性状的变化。B优827在分蘖期轻度水分胁迫、重度水分胁迫下都表现为抗干旱能力比冈优725强;轻度胁迫和重度水分胁迫下,随着胁迫时间的增加,光合速率都会下降、活性氧物质含量上升、抗氧化酶含量也相应上升。而且重度水分胁迫下,光合速率下降迅速,活性氧及其抗氧化酶含量比轻度胁迫下耍高．但胁迫第9d酶活性出现下降．说明机体詈到了严莺的榀伤．