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11.
W. M. Van der Krieken A. F. Croes G. W. M. Barendse G. J. Wullems 《Physiologia plantarum》1988,74(1):113-118
Benzyladenine (BA) was found to regulate the number of flower buds regenerated in vitro from pedicel tissue of tobacco. Flower bud induction was particularly sensitive to BA levels in the range of 0.45 to 1.0 μ M , where a two-fold increase in concentration caused a threefold rise in the number of buds. When tissues were fed radioactive BA for 24h, only 9–12% of the counts were recovered in the original compound. The rest was present in metabolites, tentatively identified as the mono-, di- and triribotides, 7- and 9-glucosides and 9-riboside of BA. The amount of growth regulator taken up and the quantities of BA and its metabolites in the explants were all linearly related to the concentration of the medium. The internal BA concentration was ca 60% of the level in the medium after 24 h. When the concentration in the medium was raised, relatively more BA remained in the non-conjugated form. However, this change in the equilibrium between BA and the conjugates is too small to account for the steep rise in the curve representing concentration vs effect between 0.45 and 1.0 μ M . 相似文献
12.
The structure of shoots, in particular of winter buds, ofHydrangea macrophylla was examined. The non-flower-bearing shoot is usually composed of a lower and an upper part, between which a boundary is
discernible by means of a distinctly short internode. This internode is the lowermost of the upper part, and it is usually
shorter than the internodes immediately above and below, although the internodes tend to shorten successively from the proximal
to the distal part of the shoot. Variations exist in the following characters among the terminal bud, the axillary bud on
the lower part of the shoot and the axillary bud on the upper part: (1) length of bud; (2) character of the outermost pair
of leaf primordia; (3) degree of development of secondary buds in the winter bud; and (4) the number of leaf primordia. Usually,
the terminal bud contains several pairs of foliage leaf primordia with a primordial inflorescence at the terminal of the bud,
but the axiallary bud contains only the primordia of foliage leaves in addition to a pair of bud scales. 相似文献
13.
Summary Callus cultures ofPicea engelmannii (Parry, Engelmann spruce) were initiated and established from mature embryos cultured on von Arnold and Eriksson’s medium
(AE) supplemented with N6-benzyladenine (10μM) and naphthalene acetic acid (10 μM). Cultures were maintained by subculture at 3-to-4-wk intervals. After three subcultures, callus was transferred to AE medium
with only N6-benzyladenine (25 μM). Adventitious buds appeared on the surface of the callus after 2-to 4-wk and grew to adventitious shoots on AE medium without
growth hormones or on AE medium with kinetin (0.1 μM). Shoot-forming capacity was maintained through 7 further subcultures.
This study was supported by the Natural Sciences and Engineering Research Council of Canada grant G1438 to T. A. Thorpe and
D. I. Dunstan. 相似文献
14.
Christina Lyra Harri Savilahti Dennis H. Bamford 《Molecular & general genetics : MGG》1991,228(1-2):65-69
Summary Using electroporation with the phage PRD1 genome, we set up a high-frequency DNA transfer system for a linear dsDNA molecule with 5-covalently linked terminal proteins. The transfer was saturated when more than 100 ng of PRD1 genome was used. Electroporation efficiency was about four orders of magnitude higher than that obtained with transfection. Removal of the terminal protein abolished plaque formation, which could not be rescued by supplying the terminal protein or phage DNA polymerase or both in trans. 相似文献
15.
Rhizome induction and plantlet regeneration of Cymbidium goeringii from flower bud cultures in vitro
Apical flower buds of Cymbidium goeringli Reichenbach fil. (ca 2 mm long) exeised from infloreseences (ca 5 cm long) were explanted on modified Murashige & Skoog medium (=MS medium) supplemented with N6-benzyladenine (BA) and -naphthaleneacetic acid (NAA). Within 107 days of culture, swelling growth, chlorophyll synthesis, and subsequent rhizome differentiation were observed. MS medium containing 0.1 mg l-1 BA and 10 mg l-1 NAA was found to be optimal for initiating rhizome development and subsequent plantlet regeneration.Explants cultured on MS medium supplemented with 1 mg l-1 NAA alone formed a mass of rhizome branches. Multiple shoots of rhizome branches were induced from apical segments when rhizomes were transferred to MS medium containing 0.1 mg l-1 BA and 10 mg l-1 NAA.Abbreviations NAA
-naphthaleneacetic acid
- BA
N6-benzyladenine 相似文献
16.
大鼠离体左室乳头肌固定于最适初长位,逐步递减“后荷”获得一系列等张收缩的张力、长度缩短程度和速度。结果发现:(1)收缩末期张力-长度关系(ESTLR)为指数曲线,回归方程 T=ar~(-bL)-K 拟合的优度明显高于线性方程拟合的优度(P<0.001),其中 a,k 分别代表总张力和静息张力,b 为曲线的弯曲度;(2)在高钙(4mmol/L)或去甲肾上腺素(NE10~(-6)mol/L)作用下,ESTLR 右上移位,a,b 和无张力缩短速度 L_O 均增大(P均<0.01),尤以高钙时的变化更明显,(3)NE 使张力-速度曲线的右上移位比高钙显著。这提示大鼠离体心肌的 ESTLR 呈非线性特征,参数 a,b 及长度轴截距 L_O 对收缩强度的变化敏感,但对收缩速度改变的敏感性可能比经典的力学指标低。 相似文献
17.
The control of bud dormancy in potato tubers 总被引:5,自引:0,他引:5
Potato (Solanum tuberosum L.) tuber buds normally remain dormant through the growing season until several weeks after harvest. In the cultivar Majestic, this innate dormancy persisted for 9 to 12 weeks in storage at 10° C, but only 3 to 4 weeks when the tubers were stored at 2° C. At certain stages, supplying cytokinins to tubers with innately dormant buds induced sprout growth within 2 d. The growth rate was comparable to that of buds whose innate dormancy had been lost naturally. Cytokinin-treatment did not accelerate the rates of cell division and cell expansion in buds whose innate dormancy had already broken naturally. Gibberellic acid did not induce sprout growth in buds with innate dormancy. We conclude that cytokinins may well be the primary factor in the switch from innate dormancy to the non-dormant state in potato tuber buds, but probably do not control the subsequent sprout growth.Abbreviations tio 6ade
6-(4-hydroxy-3-methylbut-trans-2-enyl amino)purine, zeatin
- tio6ado
6-(4-hydroxy-3-methylbut-trans-2-enyl amino)-9--D-ribofuranosyl purine, zeatin riboside 相似文献
18.
A radioimmunoassay, combined with high-performance liquid chromatography, has been used to analyse the zeatin-type cytokinins of potato (Solanum tuberosum L. cv. Majestic) tubers and tuber buds throughout growth and storage. During tuber growth, zeatin riboside was the predominant cytokinin detected in all tissues. Immediately after harvest, the total cytokinin concentration fell dramatically in the storage tissue, largely as a consequence of the disappearance of zeatin riboside. During storage, levels of cytokinins in the storage tissue remained relatively constant, but increased in the tuber buds. In the buds of tubers stored at 2°C there was a 20-to 50-fold increase in total cytokinin over six weeks, coinciding with the natural break of innate dormancy. At 10°C the rise in the level of bud cytokinins was slower, correlating with the longer duration of innate dormancy. Injecting unlabelled cytokinins into tubers in amounts known to induce sprouting gave rise to increases in cytokinin concentrations in the buds of the same order as the increase associated with the natural break of dormancy. Metabolism of injected cytokinins was greater in non-dormant than in dormant tubers. The roles of cytokinin concentration and the sensitivity of the buds to cytokinin in the control of dormancy are discussed.Abbreviations CK
cytokinin
- FW
fresh weight
- HPLC
high-performance liquid chromatography
- RIA
radioimmunoassay
- tio6ade
6-(4-hydroxy-3-methylbut-trans-2-enylamino)-purine=zeatin
- tio6adeglc9
6-(4-hydroxy-3-methylbut-trans-2-enylamino)-9--D-glucopyranosyl purine=zeatin-9-glucoside
- tio6ado
6-(4-hydroxy-3-methylbut-trans-2-enylamino)-9--D-ribofuranosyl purine=zeatin riboside
- tio6ado-[3H]-diol
a radioactive derivative of zeatin riboside, synthesised by periodate-oxidation followed by [3H]NaBH4-reduction
- tio6AMP
6-(4-hydroxy-3-methylbut-trans-2-enylamino)-9--D-5-phosphoribofuranosyl purine=zeatin riboside 5-monophosphate
- t(ioglc4)6ade
6-(4-O--D-glucopyranosyl-3-methylbut-trans-2-enylamino)-purine=zeatin-O-glucoside 相似文献
19.
用逆行溃变(Kohnstamm,1902;Yagita,et al.,1909;Torvik,1957)局部电刺激中枢(Chatfield,1942;Magoun et al.,1942;Wang,1943)等方法进行唾液中枢的定位,所得到结果很不一致。近年Satomi(1979)等用辣根过氧化酶(HRP)浸泡猫中间一面神经或鼓索神经,观察了脑干中逆行标记细胞的分布。但用HRP直接浸泡支配猫颌下腺的神经分支尚未见报道。此外,只见到关于鼓索神经纤维类别和数量的分析的光学显微镜研究(Foley,1945),用光镜和电镜相结合分析颌下腺神经支中的纤 相似文献
20.
Takeo Suzuki 《Physiologia plantarum》1984,60(4):473-478
During leaf senescence and abscission, total nitrogen in leaves of mulberry ( Morus alba L. ev. Shin-ichinose) declined substantially whereas total nitrogen in buds, bark and stem wood increased markedly, suggesting translocation of nitrogen from senescent leaves in the autumn. After leaf abscission the winter buds and stems remained almost unchanged with respect to fresh and dry weight and total nitrogen until bud break in spring. In burst buds these parameters then increased drastically during the new growth while they decreased markedly in stems. Free arginine in the stem bark accumulated in parallel with the accumulation of total nitrogen in buds and stems in the autumn. Accumulation of proline in the wood, bark and buds also started in October but continued even after leaf-fall, increasing until mid-January (wood), mid-February (bark) and the new growth (buds). Prior to and in the early stage of bud break, proline in bark and wood decreased significantly and arginine in stem bark decreased slightly. Simultaneously, proline and arginine in the dormancy-releasing buds and asparagine, aspartic acid and glutamic acid in the buds and stems increased appreciably, suggesting that this increase in free amino acids was mainly derived from free amino acids (proline and arginine) stored in stems. The resulting marked decrease in total nitrogen and the drastic increase in asparagine in the stems and sprouting buds/new shoots were primarily due to a breakdown of protein stored in stems. 相似文献