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51.
BACKGROUND AND AIMS: Lotus japonicus 'Gifu' develops multiple axillary shoots in the cotyledonary node region throughout the growth of the plant. The origin, initiation and development of these axillary meristems were investigated. METHODS: Morphological, histological and mRNA in situ analyses were done to characterize the ontogeny of cotyledonary axillary shoot meristems in Lotus. Morphological characterization of a putative Lotus shoot branching mutant (super-accessory branches) sac, is presented. KEY RESULTS: By using expression of an L. japonicus STM-like gene as a marker for meristematic tissues, it was demonstrated that groups of cells maintained in the meristematic state at the cotyledonary axil region coincide with the sites where additional axillary meristems (accessory meristems) form. A Lotus shoot branching mutant, sac, is a putative Lotus branching mutant characterized by increased proliferation of accessory shoots in all leaf axils including the cotyledons. CONCLUSION: In Lotus, axillary shoot meristems continually develop at the cotyledonary node region throughout the growth of the plant. These cotyledonary primary and accessory axillaries arise from the position of a meristematic zone of tissue at the cotyledonary node axil region. 相似文献
52.
53.
H2O2 is involved in the dormancy-breaking effect of hydrogen cyanamide in grapevine buds 总被引:2,自引:0,他引:2
Hydrogen cyanamide (HC) is widely used to induce the breakage of endodormancy (ED) in grape and other deciduous fruit crop,
though its mechanism of action is poorly understood. Applications of HC to grapevine buds produce oxidative stress and transient
respiratory disturbances which are related to the breakage of ED. Moreover, since the expression and activity of catalase
(Cat) is inhibited by HC, enhancements in the levels of H2O2 have also been associated to the breakage of ED in grapevine buds. Here, we reported that increases in H2O2 level in HC-treated grapevine buds are due to the inhibition of Cat activity and enhancement of the respiratory activity
of buds. In addition, exogenous applications of H2O2 partially reproduced the inducing effect of HC in the breakage of ED, thus providing further support for the hypothesis that
H2O2 mediates the effects of HC. On the other hand, Mit isolated from both control and HC-treated buds respired equally well when
NADH was used as a respiratory substrate, but when succinate was used as an electron donor Mit respiration was non-detected,
suggesting that the stimulatory effect of HC on bud respiration is related to metabolic alterations leading to increase of
the concentration of NADH rather than to changes in Mit functionality. 相似文献
54.
S. Y. Park Y. W. Kim H. K. Moon H. N. Murthy Y. H. Choi H. M. Cho 《Plant Cell, Tissue and Organ Culture》2008,93(3):341-346
The effect of phytohormones on the breaking of dormancy of axillary buds in Salix pseudolasiogyne and their subsequent proliferation from nodal explants were examined. Nodal explants obtained from a 20–year-old S. pseudolasiogyne tree were cultured either on woody plant basal medium (WPM) or WPM supplemented with benzyladenine (BA, 2.2/4.4 μM), zeatin
(1.1/2.2 μM), gibberillic acid (GA3, 2.9 and 14.5 μM), and GA3 + BA (2.9 + 4.4 μM). Although axillary shoots developed in all the media, a higher percentage bud break occurred on BA supplemented
media. To corroborate the results, endogenous levels of cytokinins [Cks, N
6-isopentenyladenine (iP), zeatin riboside (t-ZR), dihydrozeatinriboside (DHZR)] and abscisic acid (ABA) were determined. On BA supplemented media, the levels of zeatin
type (Z-type) of Cks were higher than those of isopentenyladenine type of Ck in the explants, while the ABA level was low.
Axillary shoots did not grow well and became necrotic upon subculture to fresh basal WPM. In order to improve shoot growth,
they were subcultured twice at a 4-week interval on to WPM supplemented with BA (2.2/4.4 μM), GA3 (1.4 μM), or GA3 + BA (1.4 + 4.4/2.9 + 4.4 μM). Maximal shoot growth (93%) was achieved on WPM supplemented with 2.2 μM BA. Comparative analyses
of endogenous Cks revealed that higher Cks (Z-type Cks) were present in actively growing shoots. Rooting was readily achieved
when the shoots were subcultured to WPM without phytohormones. The rooted plants were acclimatized well upon transplantation. 相似文献
55.
Gülhan Vardar-Ünlü Sibel Silici Mehmet Ünlü 《World journal of microbiology & biotechnology》2008,24(7):1011-1017
The antibacterial activity of propolis has been widely investigated. Since reports dealing with antimicrobial activity of
the origin of propolis are not available, this study was carried out aiming to analyse the in vitro antimicrobial activity
of the methanol extracts of poplar type propolis and Populus (Populus nigra, P. alba, P. tremuloides) buds as its sources against standard strains of a panel of microorganisms by determining the minimum inhibitory concentration
(MIC) and minimum bactericidal concentration (MBC). The concentrations of the “poplar” phenolics were relatively high (4.5%)
and some compounds typical for P. nigra such as pinobanksin and 4,3 acetyloxycaffeate were found in the propolis sample by GC-MS. The poplar type propolis and Populus
bud exudates were found to inhibit most clinically important microorganisms in a wide spectrum including pathogenic yeasts
but not Gram-negative bacteria. 相似文献
56.
Cymbopogon nardus L. could be propagated via tissue culture using axillary buds as explants. The aseptic bud explants obtained using double
sterilization methods produced stunted abnormal multiple shoots when they were cultured on Murashige and Skoog medium (MS)
supplemented with 1.0 mg L-1 or 2.0 mg L-1 benzyladenine (BA). Stunted shoots that cultured on MS + 1.0 mg L-1 BA + 1.0 mg L-1 N6-isopentenyl-adenine (2iP) could induce elongation of shoots from about 60% of the stunted shoots. Normal multiple shoots
could be induced at the highest (19.7 shoots per bud) from the bud explants within six weeks when cultured on proliferation
medium consisted of MS supplemented with 0.3 mg L-1 BA and 0.1 mg L-1 indole-3-butyric acid (IBA). The separated individual shoot produced roots when transferred to basic MS solid medium. The
essential oils that were contained in the mature plants namely citronellal, geraniol and citronellol were also found in thein vitro C. nardus plantlets. Citronellal was the main essential oil component in the matured plants while geraniol was the main component in
thein vitro plantlets. 相似文献
57.
梨树花芽休眠解除与活性氧代谢的关系 总被引:6,自引:0,他引:6
梨树(Pyrus bretschneideri Rehd.)自然休眠和休眠解除时,花芽的活性氧代谢发生变化.O2-·产生速率和H2O2的含量在休眠期间上升,在休眠后期下降.抗氧化系统中SOD活性在自然休眠期呈下降趋势,自然休眠结束活性上升.POD和CAT活性在自然休眠期上升.抗氧化物质AsA和GSH的含量随休眠进行而下降,休眠解除过程中重新升高.APX和GR的活性在休眠期间活性下降,休眠结束活性迅速上升.这些结果表明:花芽的休眠与活性氧的代谢有很大关系. 相似文献
58.
Lavandin (Lavandula dentata) axillary buds were grown in Linsmaier-Skoog (LS) medium solidified with 10 % bactoagar (control) and supplemented with 0.1 mg dm–3 benzyladenine (BA), 0.1 mg dm–3 indolebutyric acid (IBA) or both plant growth regulators. In the studied conditions the axillary buds developed into plantlets. The addition of BA inhibited the formation of glands by 44 % as compared with the control plantlets and also inhibited their development: these plantlets had the highest number of unbroken glands (in pre-secretory state) when compared with plantlets grown in the other conditions. The presence of BA stimulated chloroplast formation, and increased the content of essential oils by 150 % with respect to the control plantlets. It also increased their secretion, and the number of lipid droplets in the chloroplasts, cytosol and plasmalemma. On the contrary, the presence of IBA decreased the essential oil concentration in plantlets by 31 % when compared with the control ones and inhibited their secretion capacity. 相似文献
59.
60.
Cutaneous taste buds in gadoid fishes 总被引:6,自引:0,他引:6
Cutaneous taste buds occurred on the head and fins in five species of juvenile gadoid fishes from the west of Scotland, but there were significant differences in their density between regions on the fish and between species for individual regions. The highest taste bud densities were recorded on the edge of the anterior naris flap, the barbel, pelvic fin rays, snout tip and upper lip. Cod Gadus morhua and poor cod Trisopterus minutus had significantly higher taste bud densities on the first two pelvic fin rays than the other species. This appears to correspond with their more benthic lifestyle, in which the pelvic fins are frequently trailed over the sea bed when searching for prey. 相似文献