CTK5406对Ⅰ-69杨光合作用和生长的影响

试验以I-69杨Populus deltoides Bartr.cv.“lux”(I-69-55)为材料,研究了植物细胞分裂素制剂(CTK5406)对I-69杨光合作用和生长的影响,苗木分别培养于人工气侯宝和自然光下,结果表明,CTK5408对I-69杨的光合作用和生长具有明显作用。其中以施用量1g/1.5L(水培)和3g/10L(沙培)促进效果最好,使净光合速率提高16％,使生物量积累提高22％～28％。实际生产中由于田间多种因素的影响,施用量可取高限3g/株,直接埋入土中或与肥料一起施用。     

狗蔷薇细胞分裂素氧化酶基因RcCKX5的克隆及表达分析

利用RACE 技术从狗蔷薇（Rosa canina）类根体中克隆得到1 个细胞分裂素氧化酶基因cDNA全长,命名为RcCKX5。序列分析表明,RcCKX5 cDNA 全长1 815 bp,5′ UTR 104 bp,ORF 1 626 bp,3′ UTR85 bp,编码541 个氨基酸,具有CKX 家族典型的FAD（黄素腺嘌呤二核苷酸）结合域和CK（细胞分裂素）结合域。氨基酸序列多重比对和系统进化树分析显示RcCKX5 与可可TcCKX5 亲缘关系最近,与拟南芥AtCKX5、乌拉尔图小麦TuCKX5 同源性较高。荧光定量PCR 分析表明,狗蔷薇RcCKX5 在其根、茎、叶、花、果实中均有表达,根中相对表达量最高,花和果实中相对表达量较高。在狗蔷薇类根体形成发育过程中RcCKX5 的相对表达量不断升高,21 d 时达到最高,随后稍有下降,表明其可能参与了类根体的形成。6-BA 处理结果表明RcCKX5 能够快速响应6-BA 的诱导,表达量显著上调,2.5 mg · L-1 6-BA处理120 h 时,RcCKX5 的相对表达量达到最高峰。     

喷施细胞分裂素对长豇豆产量及生理生化指标的影响

为提高长豇豆产量,在塑料大棚直播栽培条件下,以长豇豆柳翠、早翠、矮虎和地豆为材料,进行随机区组试验。在现蕾期叶面喷施细胞分裂素,分别于喷后7d、14d、28d和42d取豇豆三出复叶的中间小叶测定叶绿素、丙二醛、脯氨酸和可溶性糖等生理生化指标,并比较喷施前后长豇豆的产量和叶片生理生化指标。结果表明:喷施细胞分裂素后7d和28d各长豇豆品种叶片中游离脯氨酸含量比各对照品种分别提高89.04%和73.44%,差异极显著;喷药后28d和42d各长豇豆品种叶片中可溶性糖含量比各对照品种分别提高72%和45.85%,差异极显著;喷药后14d和28d各长豇豆品种叶片中丙二醛含量比各对照品种分别降低25.21%和28.22%,差异极显著;喷药后42d各长豇豆品种叶片中叶绿素含量比对照品种提高47.65%,差异极显著。喷药后,各长豇豆品种的产量均高于对照,喷施后平均增产13.99%,差异极显著。喷施细胞分裂素能有效提高叶片游离脯氨酸、可溶性糖和叶绿素的含量,降低丙二醛含量,从而达到增产效果。     

转IPT基因水稻的抗旱性研究

水稻抗旱性研究是当前水稻研究的热点。采用农杆菌介导法将IPT基因导入籼稻IR64,并获得了254株再生植株,并对其进行PCR检测和Southern杂交分析,确定目的基因已整合到水稻中。选择两个单拷贝的转基因株系和一个野生型株系在开花期对其进行干旱胁迫,在同等水平干旱胁迫条件下,IPT转基因植株的细胞分裂素含量和叶绿素含量明显高于野生型,叶片温度稍微低于野生型,且转基因植株茎叶衰老延缓,这些结果表明IPT基因在抗旱育种及机理研究方面有积极的研究意义。     

Fungal derived cytokinins are necessary for normal Ustilago maydis infection of maize

Phytohormones derived from fungi play a key role in regulating plant–pathogen interactions; however, deciphering the separate contributions of pathogen and plant during infection has been difficult. Here, the Ustilago maydis–Zea mays pathosystem was used to investigate this chemical exchange. Ustilago maydis, the causative agent of maize smut, produces cytokinins (CK), which are a group of phytohormones responsible for directing plant development. The characteristic symptom of smut disease is the formation of tumours composed of plant and fungal tissue. Isopentenyltransferase (IPT) catalyses the rate‐limiting step in CK biosynthesis, and U. maydis strains in which the sole tRNA‐ipt gene was deleted no longer produced CKs. These deletion strains elicited fewer, smaller tumours than the pathogenic strain SG200. High performance liquid chromatography‐electrospray ionization tandem mass spectrometry (HPLC‐ESI MS/MS) was used to detect and quantify phytohormone levels in infected tissue. This revealed that key hormone changes in SG200 infections were not present in infections by deletion strains, suggesting that CK production by U. maydis is required for the altered phytohormone profile in infected tissue relative to uninfected tissue. Separate analyses indicated that U. maydis tRNA‐ipt mutants might be altered in their ability to metabolize CKs taken up from the environment. Mining the U. maydis genome identified genes encoding putative CK signalling and biosynthesis proteins.     

丹参细胞分裂素调控因子序列特征分析

细胞分裂素通过双元信号系统感知外界环境刺激并作出应答。其中细胞分裂素响应调控因子（response regulator,RR）是该双元信号系统中的重要构成。采用生物信息学的方法,对丹参（Salvia miltiorrhiza）细胞分裂素调控因子进行序列特征和组织表达特性分析。结果发现,丹参基因组中共有15个丹参细胞分裂素调控因子SmRR,序列比对与系统发生分析表明,SmRR1 ~ SmRR7与拟南芥A类RR亲缘关系比较接近,划分为A类RR,SmRR8 ~ SmRR15与拟南芥B类RR亲缘关系近,归为B类;在A类SmRR中,REC接受域含有保守的DDK残基,因此这些基因被推测有完整的功能,B类SmRR具有高度保守Myb_SHAQKYF结构域。两类SmRR的内含子、外显子组成也具有相对的保守性,顺式调控元件的分析发现,SmRR存在很多胁迫和生长调节物质的响应元件。表达量热图显示A类和B类SmRR基因分别在叶和根中表达量较高。     

Effects of CCC on the occurrence of tomato puffy fruits and the endogenous cytokinin activities

CCC treatment at flowering time suppressed the occurrence of tomato fruit puffiness in solution culture. Root application, truss spraying and whole plant spraying of CCC were all effective in correcting fruit puffiness, and truss spraying did not decrease fruit weight, unlike the other two treatments. For practical use, truss spraying might be the best method to control tomato fruit puffiness.Cytokinin contents in the xylem sap of tomatoes increased when CCC was applied to roots. This suggests that cytokinin biosynthesis in roots was increased by CCC treatment. Cytokinin activities in tomato fruits at an early developmental stage were also markedly increased by CCC treatment to roots. These results suggest that the CCC effect on the control of tomato fruit puffiness might be partly due to increased cytokinin activity in the developing fruit.     

核桃砧穗生理状态对微枝嫁接成活的影响

核桃微枝嫁接是以子苗为砧木以无根试管苗为接穗进行无性繁殖的一项新技术。子苗及试管苗生理状态对嫁接成活影响很大。真叶展开之前子苗内源细胞分裂素,生长素,含水量,葡萄糖,果糖均处于较高水平;嫁接易于成活;真叶展开后,上述生理指标急剧下降,随之嫁接成活率也降低。     

植物叶序发生的分子机制研究进展

叶序（Phyllotaxis）是指植物叶片在茎或枝条上坐落有序的排列方式。早期对叶序发育的研究工作主要集中在叶序形态学观察上,随着分子生物学的不断发展,科学家们开始揭示了这一过程背后的分子机制。研究表明,叶序发育受到多个基因的精细调控,同时,生长素和细胞分裂素等激素在叶序发育中起着重要的作用。大量的分子组分、物理因素以及复杂的调控网络共同决定了植物叶序的模式。对近年来国内外有关叶序模式调控的分子机制研究进展进行综述。     

细胞分裂素类生长调节剂对青花菜采后衰老的影响

 以青花菜‘绿皇后’品种为试材, 研究了25 ℃条件下细胞分裂素类生长调节剂KT、6-BA和 CPPU对延缓青花菜采后衰老的效果。结果表明: 3种细胞分裂素类生长调节剂处理均在不同程度上延缓了青花菜花蕾黄化和叶绿素分解, 推迟了呼吸和乙烯跃变峰出现的时间, 降低了峰值, 并维持了细胞膜稳定性。内源激素测定结果表明, 6-BA和CPPU处理使青花菜花蕾在试验的前期阶段(12～84 h) 一直保持相对较高的内源IAA和GA水平, 相对较低的内源ABA水平。3种细胞分裂素类生长调节剂以CPPU延缓青花菜衰老效果最为明显, 其次是6-BA, KT效果最弱。延缓青花菜采后衰老效果随着处理的浓度增加而增加, 以40 mg·L^-1 CPPU延缓青花菜衰老效果最佳。