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871.
小麦谷氨酸脱羧酶的纯化及部分性质研究 总被引:11,自引:0,他引:11
谷氨酸脱羧酶(glutamatedecarboxylase,GAD,EC4.1.1.15)催化谷氨酸脱羧生成γ-氨基丁酸(γ-aminobutyrate,BA),植物中已从南瓜[1]、马铃薯和林生山黧豆[2]纯化了GAD.GAD活性在禾本科作物中作为... 相似文献
872.
J. Beltrano M. G. Ronco E. R. Montaldi A. Carbone 《Journal of Plant Growth Regulation》1998,17(1):53-57
Treatment of flag leaves and ears of wheat plants with MJ (jasmonic acid methylester) (10−5 and 10−4
m) did not increase ethylene production, but it did accelerate senescence as indicated by the loss of chlorophyll. MJ also
caused the closure of stomata, and consequently the rates of transpiration and photosynthesis decreased. Early maturity shortened
the grain filling period, so the thousand grain weight was lower. Although ethylene elicited the same physiologic effects,
the syndrome of senescence by MJ is independent of the former. We conclude that senescence and death in wheat are far from
being elucidated; however, MJ and ethylene seem to participate in the phenomenon.
Received July 10, 1997; accepted January 5, 1998 相似文献
873.
抗寒锻炼对冬小麦幼苗质膜Ca^2+—ATPase的稳定作用 总被引:14,自引:0,他引:14
通过氯化铈(CeCl3)沉淀的电镜细胞化学方法,观察了抗寒锻炼对冬小麦(TriticumaestivumL.)幼苗质膜Ca2+ATPase的稳定作用,主要结果是:(1)正常温度(20℃)下生长的冬小麦幼苗(未经抗寒锻炼),其质膜上有很强的Ca2+ATPase活性反应;当经过-9℃3h的低温处理后,质膜的Ca2+ATPase活性明显降低;在处理12h后,质膜的Ca2+ATPase活性进一步降低;当处理时间延长到24h,质膜的Ca2+ATPase完全失活,同时细胞的超微结构受到破坏。(2)冬小麦幼苗在2℃低温下锻炼15d后,其质膜的Ca2+ATPase活性高于未经抗寒锻炼的小麦幼苗。抗寒锻炼后的小麦幼苗在-9℃处理3h后,质膜的Ca2+ATPase活性与低温处理前相比无明显降低;经低温处理12h,质膜仍保持较高的Ca2+ATPase活性,较同样低温处理(-9℃,12h)但未经抗寒锻炼的幼苗高;当-9℃低温处理24h后,质膜上仍可观察到Ca2+ATPase的活性反应,而且细胞的超微结构也未受到破坏。结果表明,抗寒锻炼可提高冬小麦幼苗质膜Ca2+ATPase在低温下的稳定性 相似文献
874.
The ultrastructure of the egg apparatus of the sexual (aestivum)-Salmon line (aS) and the isogenic but alloplasmic (kotschyi)-Salmon line (kS) of the Salmon system of wheat was studied by transmission electron microscopy 3 days before and during
anthesis. Additionally, the zygotic stage of aS, 17 h after pollination, was included. Metabolic activity of egg cells from
the sexual line aS was low 3 days before anthesis and increased dramatically after pollination and fertilization. This timing
of increased activity was evident because of changes occurring in the egg cell nucleus and nucleolus, polysomes, endoplasmic
reticulum and Golgi apparatus, and the completion of the cell wall around the zygote. In contrast to the sexual line, the
egg cell of the parthenogenetic line showed high activity 3 days before anthesis. The metabolic and ultrastructural characters
observed in the nucleus and cytoplasm of the kS line 3 days before and during anthesis corresponded with those of the isogenic
sexual line aS during anthesis and 17 h after pollination, respectively. High metabolic activity observed in the persistent
synergid of kS may be connected with the occurrence of additional embryos in seeds (twins) of this line.
Received: 25 November 1997 / Revision accepted: 16 April 1998 相似文献
875.
抗寒剂CR—4对冬小麦幼苗质膜钙泵(Ca^2+—ATPase)的稳定作用 总被引:1,自引:0,他引:1
通过磷酸铈沉淀的细胞化学观察揭示,常温下生长的冬小麦幼苗的Ca2+ATP酶活性主要定位在质膜上,同时,水浸种和抗寒剂浸种的小麦质膜Ca2+ATP酶活性没有差异。然而,小麦幼苗经-7℃冰冻处理12小时和24小时后,则表现明显的区别:水浸种的小麦幼苗质膜Ca2+ATP酶活性明显下降,直至完全失活,细胞的精细结构也同时被破坏;而经抗寒剂浸种的小麦幼苗质膜Ca2+ATP酶仍维持较高的活性,细胞结构也保持完整,显示抗寒剂对质膜Ca2+ATPase酶起着明显的稳定作用。 相似文献
876.
877.
G. P. Findlay S. D. Tyerman A. Garrill M. Skerrett 《The Journal of membrane biology》1994,139(2):103-116
An electrogenic pump, a slowly activating K+ inward rectifier and an intermittent, spiky, K+ inward rectifier, have been identified in the plasmalemma of whole protoplasts from root cortical cells of wheat (Triticum) by the use of patch clamping techniques. Even with high external concentrations of K+ of 100 m m, the pump can maintain the membrane potential difference (PD) down to –180 mV, more negative than the electrochemical equilibrium potentials of the various ions in the system. The slowly activating K+ inward rectifier, apparent in about 23% of protoplasts, allows inward current flow when the membrane PD becomes more negative than the electrochemical equilibrium potential for K+ by about 50 mV. The current usually consists of two exponentially rising components, the time constant of one about 10 times greater than the other. The longer time constant is voltage dependent, while the smaller time constant shows little voltage dependence. The rectifier deactivates, on return of the PD to less negative levels, with a single exponential time course, whose time constant is strongly voltage dependent. The spiky K+ inward rectifier, present in about 68% of protoplasts, allows intermittent current, of considerable magnitude, through the plasmalemma at PDs usually more negative than about –140 mV. Patch clamp experiments on detached outside-out patches show that a possibly multi-state K+ channel, with maximum conductance greater than 400 pS, may constitute this rectifier. The paper also considers the role of the pump and the K+ inward rectifiers in physiological processes in the cell.We thank Don Mackenzie and Kay Morris for their valuable technical assistance, particularly in the preparation of protoplasts. The project is funded by the Australian Research Council. 相似文献
878.
Erick Zagal 《Plant and Soil》1994,166(1):63-74
To examine the influence of plant-microorganism interactions on soil-N transformations (e.g. net mineralization, net immobilization) a pot experiment was conducted in a14C-labelled atmosphere by using different (two annuals, one perennial) plants species. It was assumed that variation in below-ground, microorganism-available C would influence N transformations in soil. Plant species were fertilized (low rate) with15N-labelled nitrogen and grown, during days 13 and 62 after germination, in a growth chamber with a14C-labelled atmosphere. Nitrification was inhibited by using nitrapyrin (N-Serve). During the chamber period, shoots were harvested, and associated roots and soil were collected on two sampling occasionm, e.g. after 4 and 7 weeks in the growth chamber.The distribution of net (%) assimilated14C was significantly affected by both plant and time factors, and there was a significant plant × time interaction. There were significant differences between plants in all plant-soil compartments examined as well as in the degree of the plant × time interaction.Differences in the14C distribution between plants were due to both interspecific and developmental variation. In general, when comparing15N and14C quantities between species, many of the differences found between plants can be explained by the differences determined in the weight of shoot or root parts. Despite the fact that amounts of C released were greater in ryegrass than in the other plant-treatments no unequivocal evidence was found to show that the effects of plant-microorganism interactions on soil-N mineralization were greater under ryegrass. Possible mechanisms accounting for the partitioning of N found among plant biomass, soil biomass and soil residues are discussed. 相似文献
879.
A. Kilian A. Kleinhofs P. Villand T. Thorbjørnsen O. -A. Olsen L. A. Kleczkowski 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1994,87(7):869-871
cDNA probes encoding the barley endosperm ADP-glucose pyrophosphorylase (AGP) small subunit (bepsF2), large subunit (bepl10), and leaf AGP large subunit (blpl) were hybridized with barley genomic DNA blots to determine copy number and polymorphism. Probes showing polymorphism were mapped on a barley RFLP map. Probes that were not polymorphic were assigned to chromosome arms using wheat-barley telosomic addition lines. The data suggested the presence of a single-copy gene corresponding to each of the cDNA probes. In addition to the major bands, several weaker cross-hybridizing bands indicated the presence of other, related sequences. The weaker bands were specific to each probe and were not due to cross-hybridization with the other probes examined here. The endosperm AGP small subunit (bepsF2) majorband locus was associated with chromosome 1P and designated Aga1. The endosperm AGP large subunit (bepl10) major-band locus was mapped to chromosome 5M and designated Aga7. The endosperm AGP large-subunit minor bands were not mapped. The leaf AGP large-subunit major band was associated with chromosome 7M and designated Aga5. One of the leaf AGP large-subunit minor bands was mapped to chromosome 5P and designated Aga6. A clone for the wheat endosperm AGP large-subunit (pAga7) hybridized to the same barley genomic DNA bands as the corresponding barley probe indicating a high degree of identity between the two probes. 相似文献
880.
M. K. U. Chowdhury V. Vasil I. K. Vasil 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1994,87(7):821-828
Total DNAs of plants regenerated from immature embryo-derived 2-month-old embryogenic calli of wheat (cultivars Florida 302, Chris, Pavon, RH770019) were probed with six maize mitochondrial genes (atpA, atp6, apt9, coxI, coxII, rrn18-rrn5), three hypervariable wheat mitochondrial clones (K, K3, X2), five random pearl millet mitochondrial clones (4A9, 4D1, 4D12, 4E1, 4E11) and the often-used wheat Nor locus probe (pTA71), in order to assess the molecular changes induced in vitro. In addition, protoplast-derived plants, and 24-month-old embryogenic and non-embryogenic calli and cell suspension cultures of Florida 302 were also analyzed. No variation was revealed by the wheat or millet mitochondrial clones. Qualitative variation was detected in the nonembryogenic suspension culture by three maize mitochondrial genes (coxI, rrn18-rrn5, atp6). A callus-specific 3.8-kb Hind III fragment was detected in all four cultivars after hybridization with the coxI gene. The organization of the Nor locus of the plants regenerated from Florida 302 and Chris was stable when compared to their respective control plants and calli. The Nor locus in regenerants of Pavon and RH, on the other hand, was found to be variable. However, Nor locus variability was not observed in 14 individual seed-derived control plants from either Pavon or RH sources. In Pavon, a 3.6-kb Taq I or a 5.6-kb Bam HI+ Eco RI fragment was lost after regeneration. In one of the RH regenerants, which lost a fragment, an additional fragment was observed. 相似文献