杂交水稻制种过程中籽粒内源激素含量的动态变化

穗发芽对粮食生产造成巨大的经济损失,为研究穗发芽前杂交水稻制种中杂交种子籽粒内源激素含量变化关系。采用HPLC等方法,以2个杂交水稻组合‘Y两优1号’（亲本为Y58S× R9311×）和‘II优416’（ Ⅱ-32A×R416）为材料,在水稻制种过程中进行穗发芽实验。发现组合‘Y两优1’号种子比‘II优416’易于穗发芽。同时测定了两组合在授粉15 ~27 天期间种子内源激素（IAA﹑GA1﹑ZR和ABA）含量的变化,易穗发芽的‘Y两优1号’内源激素ZR﹑IAA和GA1含量高于‘II优416’,ABA含量低于‘II优416’,且‘Y两优1号’籽粒内源GA1/ABA比值在整个过程中均大于‘II优416’。由此可见,杂交水稻制种过程中出现穗发芽现象的最主要原因是穗发芽前期种子内GA1的含量高于ABA且在发生穗发芽时GA1/ABA比值比较大。     

野生大豆AP2/RAV亚家族转录因子GsRAV3负调控拟南芥对ABA的敏感性

RAV亚家族蛋白包括1个AP2 DNA结合域和1个B3 DNA结合域。研究表明,GsRAV3是植物响应碱和ABA胁迫的重要调节因子。在碱和ABA处理下,野生大豆根系GsRAV3基因被诱导上调表达。与野生型相比,超量表达野生大豆GsRAV3的拟南芥在ABA胁迫下种子萌发状况和幼苗鲜重指标表现良好,对ABA敏感性降低。进一步研究表明,GsRAV3基因超量表达显著影响ABA合成和应答相关基因表达量。此外,GsRAV3定位于植物细胞核中,但在酵母细胞中未表现出明显的转录激活活性。综上所述,GsRAV3可能通过影响ABA合成及应答相关基因转录水平降低植物对外源ABA敏感性,表明GsRAV3在种子萌发和幼苗早期ABA信号传递过程中发挥重要作用。     

外源ABA对NaCl胁迫下紫花苜蓿矿质元素和脯氨酸含量的影响

研究不同浓度ABA处理对150 mmol/L NaCl胁迫下(水培条件)的2个不同品种紫花苜蓿Medicagosativa(维多利亚、中苜一号)矿质元素和脯氨酸含量的影响。结果表明:NaCl胁迫显著降低紫花苜蓿植物组织根、茎、叶的干质量。盐胁迫下各组织中积累大量脯氨酸,分布情况为叶茎根,外源ABA能显著提高各组织中脯氨酸的含量。且维多利亚紫花苜蓿脯氨酸含量明显高于中苜一号。与NaCl胁迫相比,添加ABA,2个不同品种紫花苜蓿Na+和Mg2+含量均降低,而K+和Ca2+含量增高,且添加浓度为10μmol/LABA时效果最好。     

甜樱桃果实NCED基因的克隆及其表达

为了进一步研究ABA在甜樱桃果实成熟过程中的作用,通过RT-PCR以及RACE-PCR方法从甜樱桃果实克隆得到了ABA合成关键酶NCED基因片段PacNCED1及其3′ 末端序列,从乙烯利处理果实中克隆得到了乙烯合成关键酶ACO基因片段PacACO1。推测的PacNCED1和PacACO1氨基酸序列与其它物种的NCEDs和ACOs氨基酸序列具有很高的同源性。通过半定量RT-PCR及定量RT-PCR方法分析了PacNCED1和PacACO1的表达模式,发现PacNCED1在甜樱桃果实发育的整个过程以及不同部位都有表达,在果肉和种子中的表达不断增加,在果实成熟之前达到最高峰,而在果柄中的表达则在果实完熟时达到最大。PacNCED1在未失水的叶片和根中有微弱表达,但在失水叶片中的表达急剧上升,表现出与失水的相关性。外源ABA和乙烯利能促进PacNCED1在果实中的表达,而NDGA和IAA对PacNCED1在果实中的表达没有显著影响。在甜樱桃果实发育过程中并没有检测到PacACO1的表达信号,但是外源乙烯利和ABA处理能诱导其在果实中的表达。     

生长抑制剂对大叶黄杨形态及光合作用的影响

目的]探究抑制剂对大叶黄杨生长的抑制作用以及对其叶片形态和光合作用的影响,为灌木绿篱的化学修剪提供技术指导。[方法]在北京林业大学林场苗圃采用3种生长抑制剂(多效唑(PP_(333))、三碘苯甲酸(TIBA)以及脱落酸(ABA))对密植成绿篱状的1年生大叶黄杨扦插苗进行叶面喷施,对其生长、叶片形态及光合作用等指标进行测定。[结果]3种抑制剂均有矮化植株、抑制新梢生长的作用,矮化效果最佳、抑制作用最强的为PP_(333),且高浓度PP_(333)对于高生长的抑制作用持效性较长。叶宽、叶厚以及叶面积在短期PP_(333)处理下高于对照。PP_(333)能提高大叶黄杨净光合速率,主要通过增加叶厚、气孔导度、叶肉导度及叶绿素含量来实现,并且PP_(333)使蒸腾速率提高的同时降低了水分利用效率。TIBA有显著减小叶长、叶宽的作用,但能使叶厚增加,且随浓度的增加作用效果增强,主要通过减小叶面积,降低叶肉导度、气孔导度、胞间CO_2浓度及叶绿素含量来降低净光合速率。ABA能增加叶面积(10 mg·L~(-1)处理除外)、叶长以及减小叶片厚度,通过抑制气孔导度、叶肉导度、叶绿素含量降低净光合速率。TI-BA及ABA均通过降低蒸腾速率,使水分利用效率提高。[结论]3种抑制剂均有矮化植株、抑制新梢生长的作用,并且影响叶片发育,进而影响叶片光合作用,且800 mg·L~(-1)的多效唑对大叶黄杨具有较好的正向作用。     

Response of Leaf Tissue Structure to Exogenous ABA in Korla Fragrant Pear

To study the effects of different concentrations of Abscisic Acid(ABA) on leaf tissue structure of Korla fragrant pear and lay the foundation for the cultivation and regulation of Korla fragrant pear. Using the paraffin section method, the leaf thickness, the epidermis thickness, the palisade tissue thickness and the sponge tissue thickness were measured; palisade spongy ratio, Cell Tightness(CT) and Cell Looseness(CL) were examined after treatments with exogenous ABA. Leaf thickness, leaf palisade spongy ratio and palisade tissue thickness increased significantly after exogenous ABA treatment compared with CK, while the effect on leaf epidermis was not obvious. The leaf thickness and palisade tissue thickness increased evidently after 70 mg · L~(-1) ABA treatment by 24.89% and 41.10%, respectively. The tissue structures of leaves were more compact, while CL was lower after 70 and 90 mg · L~(-1) ABA treatments. The effects of different concentrations of exogenous ABA could increase the leaf thickness, palisade tissue thickness of Korla fragrant pear and CT, reduced the thickness of spongy tissue and CL. Among those concentrations of exogenous ABA, the effect of spraying 70 mg · L~(-1) exogenous ABA was suitable for improving cold resistance of Korla fragrant pear.     

拟南芥rd29A基因启动子克隆及其在马铃薯抗胁迫转基因中的应用

从拟南芥（Arabidopsis thaliana）基因组中用PCR技术分离了rd29A基因上游824 bp的调控序列,序列分析表明该片段与已报道的rd29A启动子有99.39%的同源性,包括缺水诱导表达元件DRE、ABA作用元件ABRE等顺式作用元件。将此片段与GUS基因连接构建了植物表达载体pBIrd,用农杆菌介导法获得了转基因马铃薯植株。对转基因植株进行G     

壳寡糖对油菜叶片光合特性的影响

寡糖能够诱导植物抵抗生物胁迫和非生物胁迫。采用酶解法获得的壳寡糖喷施油菜幼苗。利用CIRAS-2型便携式光合仪测定油菜光合特性。用5mg/L 和50 mg/L壳寡糖溶液喷施油菜的幼苗叶片后发现其叶片的净光合速率(Pn) 、气孔导度(Gs)和胞间C02浓度(Ci)显著提高;喷施5 mg/L壳寡糖比50 mg/L效果显著。L-NANE（一氧化氮合酶抑制剂）和Na2WO4（钨酸钠,脱落酸抑制剂）减弱了壳寡糖诱导的油菜幼苗光合参数提高的作用;NO（一氧化氮）及ABA（脱落酸）处理叶片的净光合速率提高。说明壳寡糖诱导了油菜幼苗光合参数的提高通过NO和ABA通路。     

On the mechanism of selectivity of the corn herbicide BAS 662H: a combination of the novel auxin transport inhibitor diflufenzopyr and the auxin herbicide dicamba

BAS 662H, a 1:2.5 combination of the semicarbazone-type auxin transport inhibitor diflufenzopyr and the auxin herbicide dicamba, is used as a post-emergence herbicide in corn. The combination has been observed to provide more effective broadleaf weed control and improved tolerance in corn than typical rates of dicamba used alone. In order to analyze this phenomenon, the uptake, translocation, metabolism and action of both compounds, applied alone and in combination, were investigated in Amaranthus retroflexus L, Galium aparine L and corn (Zea mays L). When plants at the third-leaf stage were foliarly treated with diflufenzopyr and dicamba equivalent to field rates of 100 and 250 gha-1, respectively, diflufenzopyr synergistically increased dicamba-induced 1-aminocyclopropane-1-carboxylic acid (ACC) synthase activity and ethylene formation in G aparine and even more in A retroflexus, followed by accumulations of (+)-abscisic acid (ABA) in the shoot tissue within 20 h. This correlated with subsequent growth inhibition, hydrogen peroxide overproduction and progressive tissue damage. Diflufenzopyr also enhanced the activity of other auxin herbicides, such as quinclorac and picloram, and of the synthetic auxin, 1-naphthaleneacetic acid. After foliar and root application of [14C]diflufenzopyr, alone or as BAS 662H, considerably lower tissue concentrations and systemic translocation of radioactivity beyond treated plant parts were found in corn, compared to G aparine and particularly A retroflexus. Furthermore, diflufenzopyr decreased foliar uptake of [14C]dicamba by c 50% selectively in corn, compared to the treatment alone. Metabolism of [14C]diflufenzopyr was more rapid in corn than in the weed species. In combination, the two compounds had no mutual effect on their metabolic degradation. In BAS 662H, diflufenzopyr synergizes the herbicidal activity of dicamba in sensitive weed species. In corn this effect is prevented by a more rapid metabolism of diflufenzopyr, coupled with lower uptake and translocation. Selectivity of BAS 662H is additionally favoured by a higher crop tolerance to dicamba because of reduced foliar uptake of this herbicide in corn under the influence of diflufenzopyr.     

ABA、多效唑和烯效唑提高狗牙根抗旱性的效应

研究了ABA、多效唑(PP333)和烯效唑(S—3307)对矮生狗牙根抗旱性的影响。结果表明,在干旱条件下,ABA,PP333和S—3307均提高了矮生狗牙根的相对含水量,提高了抗旱性。ABA和S—3307处理后矮生狗牙根蒸腾失水量减小;50mg/L的PP333提高矮生狗牙根的过氧化物酶(POD)活性,10mg/L的S—3307提高过氧化氢酶(CAT)和POD活性,而5mg/L的ABA处理后超氧化物歧化酶(SOD)、CAT和POD活性均增高。