水稻半矮秆基因sd－g的染色体定位研究

以标志基因系和ＩＲ３６三体为工具材料,通过杂交,研究了籼稻矮秆材料双矮所携半矮秆基因ｓｄ－ｇ在染色体上的位置。结果表明：半矮秆基因ｓｄ－ｇ与标志基因系Ｍ４所携隐性主基因ｇｈ－１和Ｍ２７所携隐性主基因ｎ１表现连锁。ｓｄ－ｇ与ｇｈ－１之间的交换值为２４．３３％±３．９６％,ｓｄ－ｇ与ｎ１之间的交换值为２９．４４％±４．８１％。由于ｇｈ－１和ｎ１均位于第５染色体,因而推定ｓｄ－ｇ位于第５染色体上。     

水稻半矮秆基因sd-t的染色体定位研究

以籼型标志基因系和ＩＲ３６三体为工具材料,通过杂交研究了籼稻矮秆材料矮泰引－２所携半矮秆基因Ｓｄ－ｔ在染色体上的位置。结果表明,半矮秆基因Ｓｄ－ｔ与标志基因系０１９所携紫果皮基因Ｐｒｐ－ｂ、标志基因系Ｂ３０所携无叶舌基因１ｇ、标志基因系０２７所携灰白壳基因Ｗｈ表现连锁,ｓｄ－ｔ与Ｐｒｐ－ｂ之间的交换值为２．８５％±０．５２％,ｓｄ－ｔ与ｌｇ之间的交换值为２７．９０％±３．８１％,ｓｄ－ｔ与Ｗｈ之间的交换值为３８．６２％±２．９９％。由于Ｐｒｐ－ｂ、ｌｇ、Ｗｈ基因均位于第４染色体上,因而推定ｓｄ－ｔ基因位于第４染色体上,其排列位置可能是Ｐｒｐ－ｂ－ｓｄ－ｔ－ｌｇ－Ｗｈ。     

几个矮稈籼稻矮稈基因等位关系的初步分析

为研究不同矮秆籼稻品种矮秆基因的等位关系,选择了几种常见的、代表不同矮源的矮秆籼稻品种,分析了矮秆基因的等位关系。结果表明:南京11号、向阳矮、朝阳矮13号、广陆矮4号、1R_(24)和窄叶青的矮秆基因均互为等位。由于南京11号与广陆矮4号的矮秆基因同源于矮仔占,窄叶青的矮秆基因源于花龙水田谷,1R_(24)的矮秆基因源于矮脚乌尖,故可认为:矮仔占、花龙水田谷、矮脚乌尖、向阳矮和朝阳矮13号的矮秆基因均可能互为等位。     

高秆突变体Mh—1的株高遗传研究

Ｍｈ－１是从矮秆品种桂朝２号辐射诱变后代中产生的高秆突变体。用Ｍｈ－１与ｓｄ－１矮秆、非ｓｄ－１矮秆和普通高秆材料杂交,通过对Ｆ１、Ｆ２、Ｆ３等世代以及测交后代的株高进行遗传分析,结果表明,Ｍｈ－１的高秆特性是由１对隐性抑制基因控制的,该抑制基因能调节ｓｄ－１基因的表达,而对由非ｓｄ－１基因控制的矮秆没有抑制作用,这一隐性抑制基因暂时被定名为ｉ－ｓｄ－１（ｔ）。还讨论了该基因的遗传学意义和可能的育     

水稻半矮生基因sd－1的遗传性状表现──Ⅳ．半矮生性与大粒性的结合

为克服水稻半矮生基因ｓｄ－１减小粒重的副作用,培育了半矮生粳稻型大粒品种。本研究用具有大粒基因ｌｋ－ｆ的高秆品种房吉和具有半矮生基因ｓｄ－１系统ＳＣ－ＴＮ１的杂种进行了鉴定分析。结果表明,选育的半矮生系统的千位重均较ＳＣ－ＴＮ１有所提高,并出现了千粒重３０克以上的系统。亲子代的相关分析表明,粒长间有高度的正相关。充分说明,ｓｄ－１的半矮生性和大粒性的结合是可能的。因此指出,通过选择适当的大粒种质资源与ｓｄ－１基因组合,使半矮生性的抗倒伏和大粒的丰产性一体化,可以培育成丰产性更高的粳稻品种。     

牡丹冬季到内催花过程中内源激素含量的变化

牡丹品种朱砂垒（Ｐａｅｏｎｉａ ｓｕｆｆｒｕｔｉｃｏｓａ Ａｎｄｒ．ｃｖ．Ｚｈｕｓｈａｌｅｉ）在冬季室内催花过程７种内源激素含量变化不同。玉米素核苷（Ｚ＋ＡＲ）、生长素（ＩＡＡ）和赤霉素（ＧＡ３）的含量在花生长发 处于较高水平;而脱落酸（ＡＢ）、异戊烯基腺苷（ＩＰ＋ＩＰＡ）、二氢玉米素核苷（ＤＨＺ＋ＤＨＺＲ）、赤霉素（ＧＡ４）的含量低于上述３种内源激素。激素平衡方面,ＧＡｓ／ＡＢＡ、ＣＴＫｓ／ＡＢ     

葡萄果实中脱落酸结合蛋白的存在及其性质

葡萄果实微粒体上存在高亲和力的脱落酸（ＡＢＡ）结合位点,这些位点与ＡＢＡ的结合具有饱和性,高亲和力及低容量。胰蛋白酶或ＤＴＴ处理可以使该位点的特异结合活性下降约９０％,表明此结合位点是一种蛋白质,故称为ＡＢＡ结合蛋白,它含有维系蛋白质特定构象的二硫键。该蛋白与ＡＢＡ反应的最适ｐＨ为６．０,说明与配基结合部位可能存在带有正电荷的氨基酸残基,结合活性在２５℃高于０℃,结合反应达到动态平衡需要３０ｍｉｎ     

花生种子内源ABA含量变化及其与活力的关系

花生（Ａｒａｃｈｉｓ ｈｙｐｏｇａｅａ Ｌ．）种子发育过程中,胚轴内源ＡＢＡ 含量一直是增加的;种皮内源ＡＢＡ含量在果针入土后４０ ｄ 最大,然后急剧下降;子叶内源ＡＢＡ 含量在果针入土后６０ ｄ 出现高峰,然后有轻微下降。种子活力指数和萌发时内源ＡＢＡ 的净下降量有密切关系。甘露醇可促进离体胚内源ＡＢＡ 合成,１－甲基－３－苯基－５（３－［三氟甲基］－苯基－４－（１氢）－吡啶）抑制子叶内源ＡＢＡ 的合成,子叶和胚轴存在不同的ＡＢＡ 合成途径。种子早熟和早萌处理时,内源ＡＢＡ 含量都下降,胚轴在种子由发育向萌发转换中起着十分重要的作用     

天然型与非天然型脱落酸的生物活性比较

采用新方法精制脱落酸（ＡＢＡ）异构体试样,提高了（Ｓ）－（＋）－ＡＢＡ与（Ｒ）－（－）－ＡＢＡ两对映体纯度。抑制生长试验和残留量分析以及气孔闭合试验表明：天然型（Ｓ）－（＋）－ＡＢＡ活性显著高于非天然型（Ｒ）－（－）－ＡＢＡ或（ＳＲ）－（±）－ＡＢＡ。抑制莴苣种子发芽５０％的活性强度,（Ｓ）－（＋）－ＡＢＡ约是（Ｒ）－（－）－ＡＢＡ的５倍,（ＳＲ）－（±）－ＡＢＡ介于两者之间。抑制萝卜下胚轴生长试验,最显著有效期为２～６ｄ,生理作用期约为一周,（Ｓ）－（＋）－ＡＢＡ活性是（Ｒ）－（一）－ＡＢＡ的３．５倍。鸭跖革气孔闭合试验,（Ｓ）－（＋）－ＡＢＡ活性比（Ｒ）－（－）－ＡＢＡ高１倍。     

荔枝和龙眼种子发育过程中ABA含量及对源ABA敏感性的变化

在荔枝和龙眼种子发育过程中,内源ＡＢＡ水平先是上升,至大约７８－８０ＤＰＡ时出现高峰,之后两者ＡＢＡ含量均不断下降。果实成熟时采收的种子,ＡＢＡ含量比高峰时分别下降近６倍。另外,随着种子的发育,种子及其胚轴对外源ＡＢＡ的敏感性亦持续下降,１０＾－４ｍｏｌ／ＬＡＢＡ可以完全抑制９０ＤＰＡ前的荔枝和龙眼种子的萌发,但对成熟种子１０＾－２ｍｏｌ／ＬＡＢＡ亦不能抑制萌发。龙眼种子离体胚轴的ＳＡＢＡ高于荔枝     

Possible correlation between high temperature-induced floret sterility and endogenous levels of IAA,GAs and ABA in rice (<Emphasis Type="Italic">Oryza sativa</Emphasis> L.)

In order to explore the possible physiological mechanism of high temperature induced sterility in rice, we examined the floret sterility and endogenous plant growth regulator contents in pollens of two hybrid rice cultivars Shanyou63 and Teyou559 that are tolerant and susceptible to high temperature, respectively. Indexes of floret sterility, pollen activity, and variation of endogenous indole-3-acetic acid (IAA), gibberellic acids (GAs), abscisic acid (ABA), free proline and soluble proteins in anthers were measured. We found that during the course of high temperature treatment, both cultivars exhibited a marked decrease in pollen activity, pollen germination and floret fertility; however, the high temperature tolerant Shanyou63 showed a much slower rate of decrease than the high temperature susceptible Teyou559. In addition, anthers of both cultivars displayed a decrease in the contents of IAA, GAs, free proline and soluble proteins but an increase in the ABA content. Yet compared to Teyou559, Shanyou63 retained significantly higher levels of free praline and GAs and a lower level of ABA, along with higher pollen vigour and pollen germination rate even after prolonged high temperature treatment. Our study suggests a possible correlation between pollen viability/floret sterility and high temperature-caused changes in IAA, GAs, ABA, free proline and soluble protein contents. The severity in these changes may reflect the variation of rice cultivars in their heat stress sensitivities for floret development.     

The Arabidopsis ABA-deficient mutant aba4 demonstrates that the major route for stress-induced ABA accumulation is via neoxanthin isomers

A novel abscisic acid (ABA)-deficient mutant, aba4, was identified in a screen for paclobutrazol-resistant germination. Compared with wild-type, the mutant showed reduced endogenous ABA levels in both dehydrated rosettes and seeds. Carotenoid composition analysis demonstrated that the defective locus affects neoxanthin synthesis. The ABA4 gene was identified by map-based cloning, and found to be a unique gene in the Arabidopsis genome. The predicted protein has four putative helical transmembrane domains and shows significant similarity to predicted proteins from tomato, rice and cyanobacteria. Constitutive expression of the ABA4 gene in Arabidopsis transgenic plants led to increased accumulation of trans-neoxanthin, indicating that the ABA4 protein has a direct role in neoxanthin synthesis. aba4 mutant phenotypes were mild compared with previously identified ABA-deficient mutants that exhibit vegetative tissue phenotypes. Indeed, ABA levels in seeds of aba4 mutants were higher than those of aba1 mutants. As aba1 mutants are also affected in a unique gene, this suggests that ABA can be produced in the aba4 mutant by an alternative pathway using violaxanthin as a substrate. It appears, therefore, that in Arabidopsis both violaxanthin and neoxanthin are in vivo substrates for 9-cis-epoxycarotenoid dioxygenases. Furthermore, significantly reduced levels of ABA were synthesized in the aba4 mutant on dehydration, demonstrating that ABA biosynthesis in response to stress must occur mainly via neoxanthin isomer precursors.     

ABA regulates apoplastic sugar transport and is a potential signal for cold-induced pollen sterility in rice

Cold temperatures cause pollen sterility and large reductions in grain yield in temperate rice growing regions of the world. Induction of pollen sterility by cold involves a disruption of sugar transport in anthers, caused by the cold-induced repression of the apoplastic sugar transport pathway in the tapetum. Here we demonstrate that the phytohormone ABA is a potential signal for cold-induced pollen sterility (CIPS). Cold treatment of the cold-sensitive cultivar Doongara resulted in increased anther ABA levels. Exogenous ABA treatment at the young microspore stage induced pollen sterility and affected cell wall invertase and monosaccharide transporter gene expression in a way similar to cold treatment. In the cold-tolerant cultivar R31, ABA levels were significantly lower under normal circumstances and remained low after cold treatment. The differences in endogenous ABA levels in Doongara and R31 correlated with differences in expression of the ABA biosynthetic genes encoding zeaxanthin epoxidase (OSZEP1) and 9-cis-epoxycarotenoid dioxygenase (OSNCED2, OSNCED3) in anthers. The expression of three ABA-8-hydroxylase genes (ABA8OX1, 2 and 3) in R31 anthers was higher under control conditions and was regulated differently by cold compared with Doongara. Our results indicate that the cold tolerance phenotype of R31 is correlated with lower endogenous ABA levels and a different regulation of ABA metabolism.     

ABA Levels and Sensitivity in Developing Wheat Embryos of Sprouting Resistant and Susceptible Cultivars

A sprouting-resistant and a sprouting-susceptible wheat cultivar were utilized to examine the role of ABA levels and sensitivity responses in wheat embryonic germination. Endogenous embryonic ABA levels were measured in both cultivars throughout grain maturation utilizing a new and sensitive ABA immunoassay. Embryonic ABA levels of each cultivar were similar with the sprouting-susceptible cultivar having about a 25% lower ABA level than that of the sprouting-resistant cultivar. Larger differences between the cultivars were noted in sensitivity to ABA, as measured by capability of ABA to block embryonic germination. ABA inhibited embryonic germination much more effectively in the sprouting-resistant cultivar.     

Quantitative Analysis of Endogenous Gibberellins in Normal and Dwarf Cultivars of Rice

Endogenous levels of gibberellins in shoots and ears of twodwarf rice (Oryza sativa L.) cultivars, Tan-ginbozu (dx mutant)and Waito-C (dy mutant), were analyzed and compared with thoseof normal rice cultivar, Nihonbare. The endogenous levels of13-hydroxylated gibberellins in Tan-ginbozu were much lowerthan those in Nihonbare. In Waito-C, the levels of GA₁₉ andGA₂₀ in the shoots were higher but that of GA₁ was lower thanthe levels of these gibberellins in Nihonbare. These resultssupport the hypothesis that the dy gene controls the 3ß-hydroxylationof GA₂₀ to GA₁ while the dx gene controls a much earlier stepin the gibberellin biosynthesis. Our results indicate that GA₁is the active gibberellin that regulates the vegetative growthof rice. The endogenous levels of GA₄ in the ears of the twodwarf cultivars of rice were higher than the level of GA₄ inthe ears of the normal cultivar, Nihonbare suggesting that thebiosynthesis of gibberellin is not blocked in the anthers ofthe dwarf rice. (Received April 27, 1989; Accepted July 12, 1989)     

The difference of cadmium accumulation between the indica and japonica subspecies and the mechanism of it

Many studies have shown genotypic differences in Cadmium (Cd) accumulation among rice cultivars, and concentrations in shoots and grains are generally higher in indica rice cultivars than in japonica rice cultivars, but the mechanism remains unknown. The main objective of this study was to investigate differences in heavy metal accumulation between rice subspecies through the analysis of 46 indica cultivars and 30 japonica cultivars. At the seedling stage, the mean Cd concentrations in the shoots of indica subspecies were significantly higher than those in japonica subspecies (1.22-fold), but this pattern was not observed in the roots. At the filling stage, the mean Cd concentrations in the shoots and spikes of indica subspecies were 1.66- and 2.14-fold higher than the respective concentrations in japonica subspecies. At the harvest stage, the mean Cd concentrations in the shoots and brown rice of indica subspecies were 1.61- and 2.27-fold higher than the respective concentrations in japonica subspecies. These results indicate that root-to-shoot and shoot-to-grain translocation, rather than Cd absorption in the roots, may be the key processes that determine the differences in Cd accumulation among rice subspecies. Gene expression analysis revealed that overall, the expression levels of the Cd transporter gene OsNramp1 notably increased (22.46-fold), but the expression levels of OsHMA2, OsHMA3 and OsNRAMP5 were not significantly changed at the seedling stage in the 76 cultivars exposed to Cd; the expression levels of OsNramp1 were positively correlated with the Cd concentrations in spikes at the filling stage. In addition, a significant difference was observed in the expression levels of OsNramp1 between the indica and japonica subspecies, which may explain the higher Cd concentrations in roots but lower Cd concentrations in spikes and brown rice for the japonica subspecies. Together, these results demonstrate that OsNramp1 may be the most important gene among the four selected genes in the promotion of Cd uptake by roots and transfer of Cd into spikes and eventually into brown rice.     

长穗颈水稻的内源GA1、IAA和ABA含量变化

分别以携有长穗颈基因eui1、eui2和野生型基因Eui的协青早不育系和保持系6个水稻品种为材料,测定它们在抽穗始期植株中内源GA1、IAA和ABA含量的变化。结果表明,携有eui1和eui2基因的水稻可以在植株体内产生大量内源GA1,携有eui1基因的GA1含量比携有eui2基因的高。携有eui1基因的ABA含量最高,携有eui2基因的其次,而携有Eui基因的最低。IAA含量也表现出同样的趋势。表明长穗颈基因主要是通过调节内源GA1含量促进水稻最上节间的剧烈伸长。     

Light Inhibition of Shoot Regeneration Is Regulated by Endogenous Abscisic Acid Level in Calli Derived from Immature Barley Embryos

Shoot regeneration in calli derived from immature barley embryos is regulated by light conditions during the callus-induction period. Barley cultivars Kanto Nijo-5 (KN5) and K-3 (K3) showed lower efficiency of shoot regeneration in a 16-h photoperiod during callus-induction than those in continuous darkness, whereas shoot regeneration was enhanced in cultures under a 16-h photoperiod in Golden Promise (GP) and Lenins (LN). These cultivars were classified as photo-inhibition type (KN5 and K3) or photo-induction type (GP and LN) according to their response to light. Contents of endogenous plant hormones were determined in calli cultured under a 16-h photoperiod and continuous darkness. In photo-inhibition type, higher accumulation of abscisic acid (ABA) was detected in calli cultured under a 16-h photoperiod, whereas calli showed lower levels of endogenous ABA in continuous darkness. However, cultivars of photo-induction type showed lower levels of ABA in calli cultured under both light conditions, similarly to photo-inhibition type in continuous darkness. Exogenous ABA inhibited the callus growth and shoot regeneration independent of light conditions in all cultivars. In photo-inhibition type, lower levels of endogenous ABA induced by ABA biosynthesis inhibitor, fluridone, reduced the photo-inhibition of shoot regeneration. Expression of ABA biosynthesis gene, HvNCED1, in calli was regulated by the light conditions. Higher expression was observed in calli cultured under a 16-h photoperiod. These results indicate that ABA biosynthesis could be activated through the higher expression of HvNCED1 in a 16-h photoperiod and that the higher accumulations of ABA inhibit shoot regeneration in the photo-inhibition type cultivars.     

Seasonal Changes of GA1, GA19 and Abscisic Acid in Three Rice Cultivars

The levels of endogenous gibberellin A₁ and A₁₉ (GA₁ and GA₁₉)and abscisic acid (ABA) in three rice (Oryza sativa L.) cultivars,Nihonbare (normal), Tan-ginbozu (semid-warf) and Tong-il (semi-dwarf),were measured at various stages of internode elongation andear development. GA₁₉ was the main GA in Nihonbare and Tong-ilthroughout the life cycle but was not detected in Tan-ginbozu.The levels of GA₁ in the ears of all three cultivars were lowand reached their maxima after anthesis. Similarly, the earsof all three cultivars contained high ABA levels which peakedafter anthesis. Shoots contained low quantities of ABA throughoutthe life cycle. The roles of GAs and ABA are discussed withrespect to physiological phenomena, such as internode elongation,ear development and dwarfism. (Received May 9, 1981; Accepted July 18, 1981)     

A relationship between tolerance to dehydration of rice cell lines and ability for ABA synthesis under stress.

Plant dehydration is commonly caused by some adverse environmental conditions such as salinity, drought and freezing. As the plant hormone abscisic acid (ABA) is involved in responses to water stress, we studied its putative relationship with the degree of tolerance to these abiotic stresses. For this purpose we used cell lines that had been established from mature embryos of rice (Oryza sativa L, cvs. Bahia and Bomba), and selected by their high (L-T) or low (L-S) levels of tolerance to each type of stress. Tolerance of rice calli to either osmotic, saline, or freezing stress was generally improved by a previous treatment with ABA. This ABA effect was evident in those callus lines with low tolerance (L-S), as their ability to recover from stress increased up to three fold. Independent of the cultivar used, there were no significant differences in the endogenous ABA contents between untreated L-T and L-S lines. However, upon stress, the increase in endogenous ABA was higher in L-T than in L-S lines. These results, together with those obtained by using Fluridone, an inhibitor of ABA synthesis, show that differences in the level of cell tolerance to osmotic, saline and freezing stress are related to their different capacity of ABA synthesis under stress conditions.