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1.
Jan Kpczyski 《Physiologia plantarum》1986,67(4):584-587
The role of gibberellins in the germination of seeds of Amaranthus caudatus L. was examined. Tetcyclacis (BAS 106), an inhibitor of gibberellin biosynthesis, inhibited germination of the seeds. The inhibition caused by BAS 106 was antagonised by gibberellin A4+7 (GA4+7 ). Ethephon (2-chloroethylphosphonic acid) and 1-aminocyclopropane-1-carboxylic acid (ACC) could replace GA4+7 . Ethephon and ACC counteracted also the side effects of BAS 106 that are not reversible by GA4+7 . The rate of seed germination was not increased by gibberellin in the presence of aminoethoxyvinylglycine (AVG). AVG increased the effect of BAS 106. GA4+7 could not reverse the effect of BAS 106 when AVG was simultaneously applied. The results indicate that the biosynthesis of endogenous gibberellins may be required for germination of A. caudatus seeds and that main physiological effects of GA4+7 on seed germination may depend on ethylene biosynthesis. 相似文献
2.
The effect of the plant growth retardants ancymidol. mefluidide and uniconazole on germination of two melon accessions differing in their ability to germinate at 14°C was examined. The accessions were the cold sensitive Noy Yizre'el and the cold tolerant Persia 202. The three growth retardants were able to delay the germination of intact Noy Yizre'el seeds, but did not affect that of intact Persia 202 seeds. On the other hand germination of decoated seeds of both accessions was unaffected by these inhibitors at normal oxygen concentration, but was inhibited at 5% oxygen. When gibberellin-like activity was measured by a dwarf rice biological assay following HPLC fractionation, it was found that seeds of Persia 202 contained much more gibberellin-like activity than Noy Yizre'el seeds. Among the extracted compounds several endogenous gibberellins were identified by combined gas chromatography-mass spectrometry (GC-MS). They included GA4 , GA20 , GA1 and GA3 in Noy Yizre'el and GA34 , GA20 , GA1 and GA8 in Persia 202. It is suggested that the better germination of intact Persia 202 seeds, compared to Noy Yizre'el seeds at low temperature and low oxygen concentration, is due to a higher endogenous level of GA and a better seed coat permeability to oxygen. 相似文献
3.
Halińska, A. and Lewak, St. 1987. Free and conjugated gibberellins in dormancy and germination of apple seeds.
The presence of gibberellin A4 (GA4 ) was confirmed in partly stratified seeds of apple ( Malus domestica Borb., cv. Antonówka) by mass spectrometry of the methyl ester. Levels of free and conjugated gibberellins A4+7 and A9 changed during drying of mature seeds, during cold and warm stratification, as well as during germination of dormant and non-dormant embryos. The temporary rise in GA4+7 during cold stratification and during the culture of dormant embryos as well as the lack of it under conditions of warm stratification, allowed us to postulate a role for GA4+7 in the removal of dormancy. In addition, GA9 was absent in dormant embryos and increased during cold stratification and during the culture of non-dormant embryos. This suggests the involvement of GA9 , in induction of normal development of the seedling. The equivalence between changes in free and conjugated GAs suggests that formation and hydrolysis of conjugates are involved in the control of the physiologically active levels of free GA4+7 and GA9 . 相似文献
The presence of gibberellin A
4.
Gibberellin-biosynthesis and -sensitivity mediated stimulation of seed germination of Sisymbrium officinale by red light and nitrate 总被引:2,自引:0,他引:2
Light stimulated seed germination of Sisymbrium officinale (L.) Scop, (hedge mustard) by means of two different mechanisms. Light effect I was absolutely dependent on the simultaneous presence of nitrate. Without nitrate, red (R) irradiated seeds did not escape from the antagonizing action of far-red (FR) irradiation. The data indicated that nitrate acted as a cofactor at the level of the FR absorbing form of phy-tochrome (Pfr ). The combined action of R and nitrate could be replaced by addition of the gibberellins 4 and 7 (GA,4+7 ). This action could be inhibited by the growth re-tardant tetcyclacis, an inhibitor to GA biosynthesis in cell free systems and intact plants. The action of tetcyclacis was fully neutralized by GA4+7 . It is concluded that the combination of R and nitrate stimulated GA biosynthesis. Omission of nitrate from the incubation medium enabled the study of light effects apart from G A biosynthesis. In such conditions R stimulated the sensitivity to GA4+7 , (light effect II). The two light effects could also be distinguished by their different reactions to the temperature of a pre-treatment in water and darkness. The sensitivity to R and nitrate was subject to breaking and induction of dormancy. Both processes were stimulated at rising temperatures. Due to a different optimum, breaking of dormancy prevailed at lower temperatures and induction of secondary dormancy at more elevated temperatures. The sensitivity to GA4+7 rose and fell in a comparable way during dark incubation at a broad range of temperatures. The capacity of light to stimulate GA4+7 , action did not diminish at higher temperatures, it even tended to rise. The study indicated that seed germination is regulated by an increase in both the levels of GAs and the sensitivity to GAs. 相似文献
5.
Plants of annual celery ( Apium graveolens L.) were treated with paclobutrazol during anthesis. Seeds collected from the treated plants showed a marked reduction in germination in light and failed to germinate in the dark. Application of GA4/7 to the imbibition solution reversed the inhibitory effect of paclobutrazol while gibberellic acid (GA3 ) was ineffective. Benzyladenine (BA) interaction with GA4/7 was light and concentration-dependent. At relatively low concentrations in the dark there was a synergistic effect, but at higher concentrations, especially in the light, BA, antagonized the GA4/7 effect. Seedlings emerging from the seeds from paclobutrazol-treated plants were only slightly shortened. It is suggested that paclobutrazol applied to the mother plants inhibited the biosynthesis of endogenous GAs, which normally enable the germination of annual seeds under unfavorable conditions. Exogenously applied GA4/7 fulfills the function of the absent endogenous GAs. 相似文献
6.
Olavi Junttila 《Physiologia plantarum》1981,53(3):315-318
Fifteen different gibberellins (GA's) were tested for their ability to induce elongation growth under short day conditions in seedlings of Salix pentandra L. GA's were applied either to the apex or they were injected into a mature leaf. GA3 was highly active and also GA4+7 and GA4 showed high activity. GA1 , GA2 , GA5 , GA9 , GA13 , GA20 , GA36 and GA47 showed moderate activity. GA16 , GA17 , GA27 and GA41 exhibited low or no activity in doses up to 10 μg per plant. In general, a better growth response was obtained with an application to the apex than with an injection into the leaf. 相似文献
7.
Factors affecting the induction and release of secondary dormancy in Kalanchoë seeds 总被引:2,自引:2,他引:0
Abstract. Several short daily R irradiations are required from the first day of incubation on water to induce germination of Kalanchoë seeds. When the same light treatment is given after a prolonged dark incubation period at 20°C, secondary dormancy prevents germination. Factors controlling the induction and breaking of secondary dormancy have been investigated. The induction of secondary dormancy is very temperature dependent. Locally puncturing the seed coat strongly delays it. Secondary dormancy is not induced in the presence of GA3 during the first 10 d of dark incubation, although this growth substance cannot induce dark germination. Prolonged or cyclic daily R irradiations can relieve secondary dormancy of seeds kept on water, even after a dark period of 20 d. A 24 h treatment at 4°C restores responsiveness to short R exposures of slightly secondarily dormant seeds. The synergism between GA3 and Pfr in non-dormant Kalanchoë seeds, leading to high effectiveness of even one short FR irradiation, still occurs in seeds made secondarily dormant before transfer to GA3 , but more R or FR irradiations, in combination with GA3 , are required for the release of secondary dormancy. A combination of red light and 6-benzyl-aminopurine is ineffective in removing dormancy. 相似文献
8.
A high temperature treatment of 32°C which prevents dehydration injury in celery seeds imbibed for 3 days at 17°C and then dried at 20°C, reduced leakage during rehydration, compared with seeds not given the high temperature treatment. Treatments which would normally release celery seeds from dormancy, such as low temperature imbibition or gibberellin (GA4/7 ) and benzyladenine (BA) applications had little effect on the germination of seeds exhibiting desiccation injury. However, GA4/7 did induce splitting of the seed coat and swelling of the endosperm, and this effect was enhanced by BA. It is suggested that in celery seeds high temperature prevents irreversible embryo damage, including membrane damage, caused by drying. 相似文献
9.
The effect of light and exogenous gibberellic acid on respiration pathways during germination of tomato seeds 总被引:1,自引:0,他引:1
Tomato (Lycopersicon esculenlum Mill. cv. Taiwan Red) seeds are typical lightsensitive seeds where light requirement can be substituted by gibberellic acid (GA3 ). During the initial stage of germination, the hexose monophosphate pathway (HMP) in seeds incubated for 24 h under white light or 12 h in 0.3 mW GA3 solution acidified with 1 M HCI for 1 h in the dark (HCl→GA3 ) was much greater than in seeds incubated for 24 h in the dark. The results were obtained from measurements of the respiration rate by man metric method of Warburg with or without iodoacetic acid, and from activities of glucose-6-phosphate dehydrogenase (EC 1.1.1.49) and aldolase (EC 4.1.2.13). Although the HMP tended to decrease at the later stage (72 h under white light or in the dark, or 36 h in HCl→GA3 ), it remained greater in light- than in dark-incubated seeds. CN-resistant respiration increased from 27–30% to 57–64% of the total respiration in seeds incubated under white light or in HCI→GA3 , while respiration of non-germinating, dark-incubated seeds remained zero. Benzohydrox–amic acid (BHAM), an inhibitor of the alternative pathway, inhibited both respiration and seed germination. It is concluded that the enhancement of HMP and the CN–resistant pathways are both controlled by Pfr , but there is no direct connection between them. 相似文献
10.
Joan M. Malcolm Alan Crozier Colin G. N. Turnbull Einar Jensen 《Physiologia plantarum》1991,82(1):57-66
Gibberellin biosynthesis pathways were investigated using isotopically-labelled C19 - and C20 -gibberellins and cell-free preparations from immature seed of Phaseous coccineus cv. Prizewinner. The initial steps in an early 13-hydroxylation pathway involved the conversion gibberellin A12 -aldehyde (GA12 -aldehyde) to GA12 which was 13-hydroxylated to yield GA53 , Metabolism of GA53 yielded GA44 . In contrast to other cell-free systems, GA44 was not further converted, either as a δ-lactone or an open-lactone structure, to the C-20 aldehyde GA19 . GA19 was, however, metabolised to GA20 , GA5 and GA1 . GA20 represented a branch point in the pathway as it was converted both to GA1 , which was an end product, and GA5 which was further converted to GA6 . Like GA1 , GA6 was also an end-product of the early 13-hydroxylation pathway.
A non-13-hydroxylation pathway involving GA4 , GA15 , GA24 GA37 and GA36 also originated from GA12 . The terminal product of this pathway was the 3β-hydroxy C19 -gibberellin, GA4 . 相似文献
A non-13-hydroxylation pathway involving GA
11.
T. Moritz 《Physiologia plantarum》1995,95(1):67-72
Short photoperiod induces growth cessation in seedlings of Norway spruce ( Picea abies (L.] Karst.). Application of different gibberellins (GAS) to seedlings growing under a short photoperiod show that GA9 and GA20 can not induce growth. In contrast application of GA, and GA4 induced shoot elongation. The results indicate that 3β-hydroxylation of GA9 to GA4 and of GA20 to GA1 is under photoperiodic control. To confirm that conclusion, both qualitative and quantitative analyses of endogenous GAs were performed. GA1 , GA3 , GA4 , GA7 , GA9 , GA12 , GA15 , GA15 , GA20 , GA29 , GA34 and GA51 were identified by combined gas chromatography-mass spectrometry in shoots of Norway spruce seedlings. The effect of photoperiod on GA levels was determined by using deuterated and 14 C-labelled GAs as intermal standards. In short days, the amounts of GA9 , GA4 and GA1 are less than in plants grown in continuous light. There is no significant difference in the amounts of GA3 , GA12 , and GA20 between the different photoperiods. The lack of accumulation of GA9 and GA20 under short days is discussed. 相似文献
12.
Effects of gibberellins A1 , A4/7 , A9 , A19 and A20 and growth retardants were studied on shoot elongation in seedlings of Salix pentandra L. The growth-retarding effects of CCC and ancymidol were antagonized by all the gibberellins tested. The novel plant growth regulator prohexadione (free acid of BX-112), which is suggested to block 3β-hydroxylation of gibberellins, effectively prevented shoot elongation in seedlings grown under long photoperiod. Initiation of new leaves was only slightly reduced. GA1 , but not GA19 and GA20 , was active in overcoming the inhibition of stem elongation of seedlings, treated with prohexadione, GA19 , GA20 and GA1 are native in S. pentandra , and the results are compatible with the hypothesis that GA1 is active per se in shoot elongation, and that the effect of GA19 and GA20 is dependent on their conversion to GA1 .
A mixture of GA4 and GA7 was as active as GA1 in promoting shoot elongation in seedlings treated with prohexadione, while GA9 showed slight activity only when applied at high doses. 相似文献
A mixture of GA
13.
Extracts of Douglas fir ( Pseudotsuga menziesii [Mirb.] Franco) shoots were purified by reversed and normal phase HPLC; gibberellin (GA)-like compounds detected by radioimmunoassay with antibodies against GA4 and the Tan-ginbozu dwarf rice micro-drop biossay were analyzed by GC-MS. Three major components were identified as GA4 , GA7 , and GA9 while smaller amounts of GA1 , GA3 and putative GA9 -glucosyl ester were also present. 相似文献
14.
Germination of the polymorphic seeds and seedling growth of Atriplex triangularis under various salinity, gibberellic acid and kinetin treatments were determined. Gibberellic acid (GA3 ; 2.9 m M ) promoted germination and growth at high NaCl concentrations (345 m M ). Kinetin (4.7 μ M ) stimulated germination at all salinities and seed sizes tested. GA3 and kinetin generally increased seedling growth at all concentrations of salinity studied. Higher concentrations of kinetin were found to be inhibitory. 相似文献
15.
为了探究影响粗茎秦艽(Gentiana crassicaulis Duthie ex Burk.)种子休眠的因素,破除休眠,寻找其种子快速萌发的方法,以干燥的粗茎秦艽种子为材料,测定种子吸水率及粗提物的活性,使用不同浓度的赤霉素(GA3)、高锰酸钾(KMnO4)、聚乙二醇(PEG6000)和过氧化氢(H2O2)溶液进行浸种处理,比较不同处理条件对粗茎秦艽种子萌发的影响。结果显示,粗茎秦艽种皮对种子吸水没有明显阻碍作用;不同浓度的种子粗提物对白菜、小麦的萌发和生长均表现出抑制作用;不同浓度的粗提物对粗茎秦艽种子自身的萌发也表现出一定的抑制作用,当粗提物浓度达到0.1 g/mL时,抑制作用最显著(P < 0.05);高锰酸钾处理可提高粗茎秦艽种子的萌发率,浓度为1.5%时效果较显著(P < 0.05),而过氧化氢处理对粗茎秦艽种子的萌发效果不如前者,此外,用500 mg/L的赤霉素浸种和300 mg/L的聚乙二醇预处理也可显著打破粗茎秦艽种子休眠(P < 0.01)。研究结果表明粗茎秦艽种子的内源抑制物是影响其休眠的因素之一;种皮的机械阻碍也在一定程度上影响了种子萌发;粗茎秦艽种子具有综合性休眠特性。高锰酸钾预处理、赤霉素浸种和聚乙二醇引发均可打破种子休眠、缩短种子出芽时间,提高种子的发芽能力。 相似文献
16.
Interaction between Pfr and growth substances in the germination of light-requiring Kalanchoë seeds 总被引:1,自引:0,他引:1
Seeds of Kalanchoë blossfeldiana Poelln. cv. Feucrblüte, incubated on gibberellic acid, become very light-sensitive through a synergism between the far-red absorbing form of phytochrome and the growth substance, which results in high physiological activity of short far-red (FR) exposures. On 2 × 10-3 M gibberellic acid (GA3 ), one saturating FR pulse is somewhat more effective than one saturating red light (R) irradiation. Fluence-response curves for R and FR confirm this observation. At lower GA3 concentrations, this difference disappears and the effects of one saturating R and FR pulse decrease in an identical way with the GA3 concentration. When two saturating irradiations, separated by 24 h are given, the effect of FR falls off faster than that of R at low GA3 concentrations. Consequently, the second irradiation must have a different impact in comparison with the first one. Of the other growth substances tested, only a mixture of gibberellins A4 and A7 had an analogous, still more pronounced effect than GA3 . Abscisic acid (ABA) inhibits the phytochrome-mediated germination of Kalanchoë , both in the absence and presence of GA3 . An antagonism between ABA and GA3 was demonstrated. 相似文献
17.
J. GIRARD 《Plant, cell & environment》1990,13(8):827-832
Abstract. The germination behaviour of two Petunia hybrida lines. M30 and Th7 , and their reciprocal hybrids was studied. Two sets of experimental conditions appeared helped to distinguish between dormant and non-dormant parental lines: (1) 25 and 35 °C in the dark, in the latter case after 2 months of dry storage at 20 °C; (2) 35 and 40 °C in the light. Photosensitivity was tested in the first case and sensitivity to GA3 in the second case. The predominance of paternal control over dormancy was evident. A maternal or tegumentary control of photosensitivity and of sensitivity to GA3 was also shown. Transferring the seeds, originally imbibed in conditions expressing primary dormancy, to conditions which previously supported their germination, allowed us to show that secondary dormancy could be easily induced when a deeper primary dormancy had already developed in the seeds. 相似文献
18.
Halińska, A., Sińska, I. and Lewak, St. 1987. Embryonal dormancy in apple seeds is controlled by free and conjugated gibberellin levels in the embryonic axis and cotyledons.
Free and conjugated gibberellins (GAs) A4+7 and A9 were determined in embryonic axes and in cotyledons of seeds of apple ( Malus domestica Borb., cv. Antonó wka) during breaking of dormancy under cold stratification. In both organs, the maximum level of free GA4+7 was found at day 30 of stratification, but the concentration was 700 times higher in axes than in cotyledons. Comparison of changes in free and conjugated GA4+7 levels during stratification allow us to suggest that the accumulation of free hormone in axes is, at the most, to 40% due to release from conjugates already present in the axis; that maximally 20% is derived from hydrolysis of cotyledonary conjugates translocated to axes; and that at least 40% originate from the novo biosynthesis of the hormone. Free and conjugated GA9 levels were similarly altered in axes and in cotyledons, markedly increasing at the end of afterripening. Both release of the free hormone from conjugates and biosynthesis of GA9 , appeared to be involved in that increase; no translocation of free or bound GA9 , between axes and cotyledons was demonstrated. 相似文献
Free and conjugated gibberellins (GAs) A
19.
Plants of Poa pratensis cv. Holt initiate inflorescence primordia when exposed to short days (SD) and low temperature, but require a secondary induction by at least 4 long days (LD) for further inflorescence development and stem elongation. Single or double applications of 10 µg per plant of gibberellins A1 , A3 , A5 and 16,17‐dihydro A5 (DHGA5 ) induced inflorescence development in a high proportion of plants in SD, but only if the plants were detillered to a single stem. Exposure to 2 LD cycles did not cause heading and flowering alone but enhanced the effect of exogenous gibberellins (GAs), bringing flowering to 100%. GA5 and DHGA5 were less effective than GA1 and GA3 in SD, especially with double applications, but were more effective than GA1 and GA3 when given together with 2 LD. The GAs had differential effects on vegetative growth and flowering, GA5 and DHGA5 causing much less leaf and stem growth than the other two GAs. Marginal induction, whether by LD or GA application, resulted in a high proportion of spikelets with viviparous proliferation. Thus, whereas GAs are inhibitory to the primary induction by SD, they can replace secondary induction by LD when vegetative growth is limited. 相似文献
20.
Potassium promotes growth in several plant tissues. Elongation growth of the hypocotyls of Amaranthus caudatus L. ev. Lalsag is mainly controlled by gibberellins, but K+ also promotes growth. In the present study the interaction of K+ with gibberellin (GA3 ) and chlorocholine chloride (CCC) has been investigated. When K+ was applied externally in the dark, hypocotyl growth was promoted in the seedlings. External application of GA3 did not promote growth in the dark. GA3 was effective in the light and K+ was synergistic with GA3 in promoting elongation. Application of CCC in the dark makes the seedlings sensitive to GA3 . The inhibition of growth by CCC was also reversed by K+ . The results indicate a possible role of K+ in GA3 induced elongation of hypocotyls. 相似文献