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排序方式: 共有271条查询结果,搜索用时 46 毫秒
241.
Deepak Pental Akshay K. Pradhan Yaspal S. Sodhi Arundhati Mukhopadhyay 《Plant cell reports》1993,12(7-8):462-467
Summary Twelve cultivars of Brassica juncea grown in different agroclimatic regions of the world were tested for their ability to regenerate in vitro from hypocotyl explants and, accordingly, were divided into three groups. One group of cultivars regenerated on MS medium supplemented with 2,4-D, BAP and with NAA, BAP combinations; another group regenerated only on MS with 2,4-D, BAP; and the third group showed very low regeneration on both of these combinations. Inclusion of silver nitrate in the medium was essential for high frequency of regeneration. In general, Indian cultivars were more responsive than the cultivars of CIS and Australian origin. Using the media optimal for regeneration and an Agrobacterium-based binary vector carrying hpt and gus-intron genes, conditions for genetic transformation of B. juncea hypocotyl explants were optimized. Transformation frequencies, identified by GUS staining at the initial stages of growth, were lower on MS medium with 2,4-D, BAP than on MS with NAA, BAP. Plants resistant to 20 g/ml hygromycin were regenerated at a frequency of 11–36% from hypocotyl explants and were shown to be transformed by Southern blotting, GUS staining and progeny analysis. 相似文献
242.
表油菜素内酯对黄瓜幼苗下胚轴过氧化物酶和IAA氧化酶活性的影响 总被引:1,自引:0,他引:1
黄瓜幼苗用0.1~1 ppm表油菜素内酯(epiBR)处理1~3d后,下胚轴中过氧化物酶活性明显低于对照;随着处理浓度的增加和处理时间的延长,与对照之间的差别愈趋增大。当浓度高于1ppm时,过氧化物酶的活性不再继续降低。表油菜素内醋对过氧化物酶活性的这种抑制作用需经约1O h的滞后期。IAA氧化酶的活性变化与过氧化物酶相似,epiBR处理时间愈长酶活性增加愈趋缓慢。 经IAA处理的下胚轴,过氧化物酶和IAA氧化酶的活性变化与对照无明显差异。这提示油菜素内酯与IAA促进生长可能是通过不同的作用方式。 相似文献
243.
In forestry, vegetative propagation is important for the production of selected genotypes and shortening the selection cycles
in genetic improvement programs. In vivo cutting production, in vitro organogenesis and somatic embryogenesis are applicable with conifers. However, with most coniferous species these methods
are not yet suitable for commercial application. Large-scale production of clonal material using cuttings or organogenesis
is hindered by rooting problems and difficulties in the maturation and conversion limit the use of somatic embryogenesis.
Economically important conifers form symbiotic relationship mostly with ectomycorrhizal (ECM) fungi, which increase the fitness
of the host tree. Several studies have shown the potential of using ECM fungi in conifer vegetative propagation. Inoculation
with specific fungi can enhance root formation and/or subsequent root branching of in vivo cuttings and in vitro adventitious shoots. Germination of somatic embryos and subsequent root growth can also be improved by the use of ECM fungi.
In addition, inoculation can increase the tree's ability to overcome the stress related to ex vitro transfer. A specific interaction between a fungal strain and tree clone occurs during root induction and germination of somatic
embryos. Multiple rooting factors exist in this interaction that complicate the predictability of the response to inoculation.
Fungal-specific factors that influence rooting responses to inoculation may include plant growth regulator production, modification
of the rooting environment, and interactions with beneficial microbes. A combination of these factors may act synergistically
to result in positive responses in tree genotypes that are compatible with the fungus. 相似文献
244.
植物荫蔽胁迫的激素信号响应 总被引:1,自引:0,他引:1
植物的生长发育与光信号密切相关, 外界光强、光质的变化会改变植物的生长发育状态。在自然或人工生态系统中, 植株个体的光环境往往会被其周围植物所影响, 导致荫蔽胁迫, 其主要表现为光合有效辐射以及红光与远红光比值(R:FR)降低。荫蔽胁迫对植物生长发育的多个时期均有影响, 如抑制种子萌发、促进幼苗下胚轴伸长及促进植物花期提前等, 这对农业生产不利, 会导致作物产量以及品质的降低。植物激素是调控植物生长发育的关键内源因子。大量研究表明, 生长素(IAA)、赤霉素(GA)及油菜素甾醇(BR)等植物激素均参与介导植物的荫蔽胁迫响应。当植物处于荫蔽胁迫时, 光信号的改变会影响植物激素的合成及信号转导。不同植物激素对荫蔽胁迫的响应各不相同, 但其信号通路之间却存在互作关系, 从而形成复杂的网络状调控路径。该文总结了几种主要植物激素(生长素、赤霉素、油菜素甾醇及乙烯)响应荫蔽胁迫的机理, 重点论述了荫蔽胁迫对植物激素合成及信号通路的影响, 以及植物激素调控荫蔽胁迫下植物生长的分子机理, 并对未来潜在的研究热点进行了分析。 相似文献
245.
Received 17 October 2000/ Accepted in revised form 22 February 2001 相似文献
246.
Nagashima A Suzuki G Uehara Y Saji K Furukawa T Koshiba T Sekimoto M Fujioka S Kuroha T Kojima M Sakakibara H Fujisawa N Okada K Sakai T 《The Plant journal : for cell and molecular biology》2008,53(3):516-529
Photoreceptors, phytochromes and cryptochromes regulate hypocotyl growth under specific conditions, by suppressing negative gravitropism, modulating phototropism and inhibiting elongation. Although these effects seem to be partially caused via the regulation of the phytohormone auxin, the molecular mechanisms underlying this process are still poorly understood. In our present study, we demonstrate that the flabby mutation enhances both phytochrome- and cryptochrome-inducible hypocotyl bending in Arabidopsis. The FLABBY gene encodes the ABC-type auxin transporter, PGP19, and its expression is suppressed by the activation of phytochromes and cryptochromes. Our current results therefore indicate that the phytochromes and cryptochromes have at least two effects upon the tropic responses of the hypocotyls in Arabidopsis: the enhancement of hypocotyl bending through the suppression of PGP19, and a PGP19-independent mechanism that induces hypocotyl bending. By the using an auxin polar transport assay and DR5:GUS expression analysis, we further find that the phytochromes inhibit basipetal auxin transport, and induce the asymmetric distribution of auxin in the hypocotyls. These data suggest that the control of auxin transport by phytochromes and cryptochromes is a critical regulatory component of hypocotyl growth in response to light. 相似文献
247.
V. Ravishankar Rai 《In vitro cellular & developmental biology. Plant》2002,38(4):347-351
Summary
Nothapodytes foetida (Wight) is a small evergreen tree and the extract from this tree is used to make the antileukaemia and antitumoral compound
camptothecin. Due to exploitation of this resource, efficient methods for rapid propagation of N. foetida are highly desirable. Multiple shoots were induced on hypocotyl segments of 20–25-d-old seedlings of N. foetida cultured on Murashige and Skoog (MS) medium supplemented with different concentrations and combinations of cytokinins. The
highest shoot multiplication was achieved on MS medium containing thidiazuron (TDZ) at the concentration of 2.2 μM. Inhibition of shoot elongation by TDZ was overcome by transferring shoot cultures to medium containing 2.2 μM benzylaminopurine which produced healthy shoots after three additional subcultures. The production of shoots was further
promoted by repeated subculturing of original explants on fresh multiplication medium after each harvesting of the newly formed
shoots. In vitro rooting was best induced (87%) in shoots excised from proliferated shoot cultures on one-fourth MS medium augmented with
5.7 μM indole-3-acetic acid and 2.4 μM indolebutryic acid (IBA). In vitro-developed shoots were also rooted ex vitro by dipping in 49 μM IBA for 10 min. In vitro- and ex vitro-rooted plants were successfully acclimatized and established in greenhouse conditions. 相似文献
248.
根癌农杆菌介导B.t.基因和CpTI基因对花椰菜的转化 总被引:16,自引:0,他引:16
用根癌农杆菌介导的方法 ,将B .t.基因和Cp TI基因分别导入花椰菜“杂交 75天”的父本和母本的无菌苗下胚轴切段细胞 ,都获得了转基因植株。经过预培养的下胚轴切段用根癌农杆菌 (LBA44 0 4/ pG BI4A2B ,含B .t .基因 ;LBA44 0 4/pBRLC ,含CpTI基因 )进行感染后 ,共培养 48h ,继续培养 30d后 ,将分化芽转移至筛选培养基上。 10d后 ,大多数分化芽的顶端变成紫色 ,2 0d后紫色芽逐渐变白死亡 ,而转化芽在选择培养基上长成小植株。小植株移至大田能正常生长、开花、结籽。PCR和Southernblot分析表明B .t和CpTI基因已整合在植物基因组中 相似文献
249.
Summary An improved protocol for shoot regeneration from hypocotyl segments of seedlings from open-pollinated seeds of lingonberry
(Vaccinium vitis-idaea L.) cultivars, ‘Ida’, ‘Splendor’, and ‘Erntesegen’, and a native clone from Newfoundland was developed. The effect of thidiazuron
(TDZ) on adventitious bud and shoot formation from apical, central, and basal segments of the hypocotyl was tested. Highly
regenerative callus was obtained from hypocotyl segments on modified Murashige and Skoog (MMS) medium containing 5–10 μM TDZ. A maximum of 10 buds and 12 shoots per apical segment for seedlings of cultivar ‘Ida’ regenerated on MMS containing
10 μM TDZ. Callus and bud regeneration frequency, callus growth, and number of buds and shoots per regenerating explant depended
not only on the specific segment of the hypocotyl, but also on parental genotype. Inhibition of shoot elongation by TDZ was
overcome by transferring shoot cultures to a shoot proliferation medium containing 1–2 μM zeatin. The optimal concentration of sucrose for shoot elongation was 20 gl−1. Shoots were rooted ex vitro on a 2 peat: 1 perlite (v/v) medium after dipping in 0.8% indole-3-butyric acid, and rooted plants acclimatized readily under
greenhouse conditions. 相似文献
250.
Strand A 《Current opinion in plant biology》2004,7(6):401-625
The function of the eukaryotic cell depends on the reciprocal interaction between its different compartments. Plastids emit signals that regulate nuclear gene expression to ensure the stoichiometric assembly of plastid protein complexes and to initiate macromolecular reorganisation in response to environmental cues. It is now clear that several different plastid processes produce signals that influence the expression of photosynthetic genes in the nucleus. The genome uncoupled (gun) mutants recently revealed one of the plastid signals, the chlorophyll intermediate Mg-protoporphyrinIX. 相似文献