A quinclorac sensitive lethality rice mutant: its discovery,genetics and potential application

In this study, we reported a quinclorac‐sensitive rice natural mutant M4017, derived from an indica restorer line 4017 of three‐line hybrid. The mutant could be killed at three‐leaf stage by quinclorac at 175 mg/l or higher, a dosage that is recommended for monocot herbs control. The mutant at flowering stages can also be effectively killed by quinclorac at 1.25–1.50 g/l or higher, which is safe for its F₁ hybrids and all other normal varieties. Genetic analysis, using the F₁, F₂ and BC₁ populations derived from this mutant and other often‐used varieties, revealed that quinclorac sensitivity/lethality was controlled by a single recessive gene, which was named quin1. This mutant has a potential application in false hybrid seed removal or mechanized production of hybrid seeds.     

栽培稻种内rDNA基因IGS序列分析及系统学意义

以普通野生稻为对照, 将rDNA基因间区(IGS)序列用于栽培稻种内不同亚种以及亚种内不同品种的亲缘关系分析。结果表明, 栽培稻种内IGS序列长度为2 130~2 145 bp, G+C含量为74.59%~75.29%, 变异位点229个, 占10.70%, 信息位点76个, 占3.51%。IGS序列中籼亚种和粳亚种之间有38个亚种标志性碱基差异, 主要分布在IGS 5′ 端近400 bp的序列中。用IGS序列构建的系统树能将栽培稻的籼亚种和粳亚种分为两大类, 亚种内不同亲缘关系的品种也能区分开。本研究结果支持爪哇稻为栽培稻中一个独立亚种的观点。     

不同水分条件下水稻籽粒形态及其与粒重的关系

运用机器视觉检测技术, 以普通杂交稻汕优63和超级杂交稻国稻6号为材料, 在幼穗分化开始至分化后30 d分别设置不同的控水处理, 通过水分仪结合称重法控制土壤含水量, 研究了稻穗及穗上不同部位籽粒的形态性状, 并分析各性状与粒重的关系。结果表明：水稻的籽粒面积、长度及千粒重对水分反应较明显, 水分亏缺对籽粒面积和粒重的影响引起比粒重(单位籽粒面积的重量)变化, 长宽比对水分也有一定反应, 宽度对水分的响应因品种而异。籽粒形态性状、产量及其构成因素均随水分亏缺的加重而有不同程度下降, 穗生长发育全阶段的控水处理影响最大, 其次是中期的重度和中度控水处理以及前期、后期的重度控水处理, 各时段控水对不同部位籽粒形态的影响与穗分化发育的顺序历期基本吻合。除粒宽与其他形态性状之间呈极显著或显著负相关以外, 其余各籽粒形态性状之间均呈极显著正相关。籽粒面积、长度及长宽比与千粒重之间存在极显著或显著的相关关系, 可以作为水稻抗旱性鉴定有效的籽粒形态指标。     

水稻及其敏感突变体苯达松抗性的生理生化差异研究

苯达松敏感致死(bentazon sensitive lethal, bsl)基因在杂交水稻(Oryza sativa L.)混播制种和杂交稻种纯度鉴定等方面具有广阔的应用前景。以水稻品种农林8号(N8)、W6154s和其对应的bsl突变体农林8号m (N8m)和8077s为材料, 分析了苯达松处理对叶片中叶绿素(Chl)含量、丙二醛(MDA)含量、氧自由基含量、净光合速率(P_n)、叶绿素荧光参数等生理生化指标的影响及苯达松含量的变化, 旨在揭示水稻苯达松抗性差异的生理机制。结果表明, 苯达松处理使bsl突变体叶片光系统II中还原性Q_A组分积累, 光合电子传递受阻, 光合能力丧失, 氧自由基伤害积累, Chl降解、质膜氧化加剧, 植株死亡。叶片中苯达松残留含量分析表明, 较强的苯达松代谢能力是抗性品种免受苯达松伤害的主要原因。     

水稻几个披垂叶突变体的表型研究及其遗传分析

随着水稻功能基因组学的发展,水稻突变体已成为研究相关基因功能与表达的良好实验材料。同时,水稻突变体还可以为当今水稻常规育种和分子育种提供新的种质资源。本文主要阐述了几个水稻披垂叶突变体在株型、株高、穗粒数、结实率、千粒重等方面的特征特性,并分析了它们在与正常植株杂交后F1、F2群体表现。研究表明,突变体与野生型正常植株杂交的F1代在经济学性状和生物学性状上均表现出超亲优势,而在F2群体中表现出有规则的分离,3个突变体中披垂叶性状均为隐性基因控制。在突变体材料MR304中,控制披垂性状的为2对隐性基因,其中1对为主效基因。在突变体材料MR168和MR312中,控制披垂性状的均为单隐性基因。     

水稻非对称混合样品中非优势DNA模板SSR标记的PCR检测

利用DNA混合池筛选分子标记可以大大提高检测效率,来自不同亲本的模板DNA的浓度一旦相差悬殊,可能影响PCR扩增结果。本文对不同稀释浓度和混合比例的模板DNA进行SSR标记的PCR扩增。结果表明,单一模板不同稀释倍数的影响不明显,但不同模板DNA竞争造成非对称混合样中非优势模板扩增量的明显降低。对于扩增效果较好的SSR标记而言,模板浓度比为1 ：7时仍可检测到低浓度模板的扩增产物。     

Enclosed stigma contributes to higher spikelet fertility for rice(Oryza sativa L.) subjected to heat stress

With global warming, rice plants may be subjected to heat stress more regularly during the heatsensitive flowering stage, causing spikelet sterility and grain yield loss.Stigma exsertion is considered to increase pollen reception and promote female reproductive success.The aim of this study was to investigate the role of stigma exsertion on spikelet fertility at high temperatures.Five rice cultivars(Liangyoupeijiu, Shanyou 63, Huanghuazhan, Nagina 22, and IR64) with differing degrees of stigma exsertion were cultivated and exposed to high temperature at anthesis.Heat-tolerant cultivars did not always show a high percentage of spikelets with exserted stigmas, and vice versa.Irrespective of the presence of more pollen grains on exserted stigmas, spikelets with exserted stigmas did not show greater spikelet fertility than spikelets with fewer exserted stigmas or hidden stigmas under heat stress.GA3 application augmented the percentage of spikelets with exserted stigmas;however, it did not increase spikelet fertility under heat stress.Spikelet fertility of whole panicles was negatively correlated with the percentage of spikelets with exserted stigmas, but positively with that with hidden stigmas.Viability of the hidden stigmas was less reduced than that of exserted stigmas under heat stress, suggesting that hidden stigmas have an advantage in maintaining viability.Heat stress delayed anther dehiscence and reduced the viabilities of both exserted stigmas and pollens, thereby causing low spikelet fertility.Together, these results suggest that high spikelet fertility does not depend on stigma exsertion and that enclosed stigma generally contributes to higher spikelet fertility and heat tolerance under high-temperature conditions during flowering in rice.     

水稻萌发期和幼苗期耐低温指标体系构建及综合评价

为探究水稻品种间耐低温性鉴定方法,以8个水稻品种和3个自育品系为材料,以种子萌发和幼苗生长指标的相对值作为耐低温性评价指标,在主成分分析的基础上,利用模糊数学中的隶属函数法对11个水稻品种进行耐低温性综合评价,16个鉴定指标中筛选出5个主成分,其中发芽势、发芽率、发芽指数、株高、根干重、根表面积和根体积可作为水稻品种耐低温性的鉴定指标。加权隶属函数法评价出11个水稻材料耐低温性强弱顺序,聚类分析结果将11个水稻材料耐低温性聚为3类,第Ⅰ类耐低温性较强,第Ⅱ类耐低温性中等,第Ⅲ类耐低温性最弱。结果为水稻材料耐低温性评价方法和这11个水稻品种的生产应用提供一定的依据。     

低植酸水稻种质资源筛选、遗传生理调控与环境生态适应性研究进展

提高或维持水稻产量的同时,提高稻米品质已成为目前水稻育种的首要目标之一。其中,通过降低籽粒中植酸等抗营养因子,增加锌、铁生物有效性以提升水稻营养品质,是目前水稻品质改良的一个重要方向。本文主要综述了水稻籽粒中植酸合成的代谢路径、低植酸水稻的筛选及相关功能基因的遗传特点、植酸生理代谢的调控网络、低植酸水稻农艺性状劣变和生态适应性降低的生理原因、籽粒植酸合成的环境调控效应等相关研究进展。可为低植酸水稻品质改良以及栽培调优提供借鉴。     

Effects of brassinolide on the growing of rice plants

Brassinosteroids are plant steroid hormones that are essential for plant growth. When germinated rice seeds were treated with brassinolide (BL), stems were elongated and root spiral formation was observed at 5 nM of BL. Such root spiral formation was not induced by other plant hormones such as auxin and gibberellin. Since weak non-steroidal brassinolide-like compound (NSBR1) also induced spiral formation, this root spiral induction can be used as the index in the search for BL-like compounds.