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1.
Yaakov Goldwasser Kaori Yoneyama Xiaonan Xie Koichi Yoneyama 《Plant Growth Regulation》2008,55(1):21-28
The germination stimulants produced by Arabidopsis thaliana, a host of root parasitic plants Orobanche spp. but not of arbuscular mycorrhizal (AM) fungi were examined. Root exudates from the hydroponically grown A. thaliana plants were subjected to reverse phase high performance liquid chromatography (HPLC) and retention times of germination stimulants
inducing O. aegyptiaca seed germination were compared with those of strigolactone standards. In addition, the root exudates were analyzed by using
HPLC linked with tandem mass spectrometry (LC/MS/MS). A. thaliana was found to exude at least three different germination stimulants of which one was identified as orobanchol. This is the
first report of strigolactone production by a non-mycotrophic plant. These results together with recent knowledge imply that
strigolactones have other unrevealed functions in plant growth and development. 相似文献
2.
低温胁迫对番茄种子萌发的影响 总被引:4,自引:0,他引:4
在人工气候箱中模拟3个低温处理(24h最低/最高温度分别设定为7℃/12℃、5℃/10℃和3℃/8℃),分析了播种后不同天数低温胁迫对番茄种子萌发的影响。结果表明:与对照(18℃/25℃)相比,低温胁迫处理的温度越低影响越大,当日最低温度达到5.0℃、日均温低于10.0℃(相当于低温胁迫处理7℃/12℃)时,对番茄种子萌发的影响较为严重;播种后越早经受低温影响越大,播种后3d内经受低温胁迫,番茄种子发芽势、发芽指数和萌发率均有较大的下降,播种6d后低温胁迫对其萌发指标的影响较小;低温胁迫影响种子萌发的原因主要是低温导致了α-淀粉酶活性下降,相对离子渗漏率增加,从而减缓了番茄种子贮藏物质的降解,影响了番茄种子萌发初期的物质与能量代谢,并增强了细胞膜的透性,导致外渗物增多。 相似文献
3.
The ability of different bacteria to inhibit Orobanche radical elongation was examined. Seeds of Orobanche aegyptiaca Pers. and O. cernua Loefl. were induced to germinate with the Growth Regulator GR24 in the presence or absence of test bacterium. Radical lengths were estimated microscopically on a scale relative to seed length (0–5 seed lengths) after 5 days of incubation at 25°C. The results indicated that Pseudomonas aeruginosa QUBC1, P. fluorescens QUBC3, Bacillus atrophaeus QUBC16, and B. subtilis QUBC18 significantly inhibited radical elongation (P≤0.01) of both O. aegyptiaca and O. cernua relative to control radicals, whereas Microbacterium hydrocarbonoxydans QUBC11 and Ochrobactrum anthropi QUBC13 showed less inhibitory effects. Other bacterial isolates had no inhibitory effects. Bacterial isolates were identified using the universal method in addition to morphological and biochemical features. The establishment of the inhibitory effect of the most promising isolates, B. atrophaeus QUBC16 and P. aeruginosa QUBC1 on radical elongation of both Orobanche spp. is a step towards utilizing such bacteria as biocontrol agents against O. aegyptiaca, O. cernua, and potentially other Orobanche species. 相似文献
4.
Slavov S van Onckelen H Batchvarova R Atanassov A Prinsen E 《Journal of plant physiology》2004,161(7):847-853
Broomrapes (Orobanche spp.) are parasitic plants, whose growth and development fully depend on the nutritional connection established between the parasite and the roots of the respective host plant. Phytohormones are known to play a role in establishing the specific Orobanche-host plant interaction. The first step in the interaction is seed germination triggered by a germination stimulant secreted by the host-plant roots. We quantified indole-3-acetic acid (IAA) and abscisic acid (ABA) during the seed germination of tobacco broomrape (Orobanche ramosa) and sunflower broomrape (O. cumana). IAA was mainly released from Orobanche seeds in host-parasite interactions as compared to non-host-parasite interactions. Moreover, germinating seeds of O. ramosa released IAA as early as 24 h after the seeds were exposed to the germination stimulant, even before development of the germ tube. ABA levels remained unchanged during the germination of the parasites' seeds. The results presented here show that IAA production is probably part of a mechanism triggering germination upon the induction by the host factor, thus resulting in seed germination. 相似文献
5.
Yasutomo Takeuchi Yumi Omigawa Masaru Ogasawara Koichi Yoneyama Makoto Konnai A. Douglas Worsham 《Plant Growth Regulation》1995,16(2):153-160
Brassinolide [2, 3, 22R,23R-tetrahydroxy-24S-methyl-B-homo-7-oxa-5--cholestan-6-one] and its related compounds, brassinosteroids, applied at the early stages of conditioning shortened the conditioning period required before clover broomrape seeds would germinate after exposure to germination stimulants, such as dl-strigol and natural stimulants from red clover (Trifolium pratense L.) root exudate. Brassinosteroids applied after conditioning increased the rate of the seed germination induced by these stimulants. The inhibitory effect of light on seed germination when it was induced by dl-strigol could be overcome by brassinosteroids. Brassinosteroids also eliminated the inhibitory effects of light and dl-strigol applied at the early stages of conditioning. GA3 was also effective in causing seed conditioning and increased the rate of the germination induced by these stimulants. There was a relationship between brassinosteroids and GA3 in many of the experiments conducted. These findings may have practical implications in increasing the effectiveness of applying germination stimulants in the field to soils for suicidal germination of broomrape seeds. 相似文献
6.
Moshe Agami 《Physiologia plantarum》1986,67(2):305-309
The effects of different soil water potentials, temperature and NaCl concentration on seed germination of Zygophyllum dumosum Boiss., a common shrub in Israeli deserts, was investigated. Seeds had to be exposed to constant field capacity conditions (–0.0316 MPa) for a minimal period of two days before germination could start. Maximal germination under such conditions occurred after four days or more. Under simulated conditions of gradual dehydration of the soil, seeds were inhibited either at low soil water potentials (–0.10 to –10.00 MPa) or at high ones (–0.002 to –0.0398 MPa). Germination of Z. dumosum was independent of temperature in the range of 10–25°C, but strongly inhibited at 30 and 35°C. At 20°C germination was inhibited by salinity of the medium but still occurred (0.5%) even at a concentration of 0.5 M NaCl. 相似文献
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8.
A short period (15–30 min) at 30° C promotes germination of seeds of Lactuca sativa L. cv. Repolhuda in darkness. Far-red light reverses this stimulation, and the escape curves for phytochrome and high-temperature action are quite similar, indicating that the two factors act at a common point in the chain of events leading to germination. It is suggested that high temperature acts by decreasing the threshold of the active, far-red absorbing, form of phytochrome (Pfr) needed to promote germination.Abbreviations FR
far-red light
- Pfr
far-red-absorbing form of phytochrome
- R
red light 相似文献
9.
A model of seed germination is proposed which uses a variable with the units of an osmotic potential (virtual osmotic potential) to integrate the effect of a constant or a varying water potential. This differs from existing models that describe the effects of fixed water potentials on germination, or the effects of fixed priming water potentials on the subsequent germination at a fixed water potential. When a seed is sown, the virtual osmotic potential is assumed to fall at a rate that depends on the ambient water potential, and on the difference between its current and a minimum value. Radicle growth is assumed to initiate when the difference between the ambient water potential and the virtual osmotic potential exceeds a threshold. The germination of carrot and onion seeds at various fixed potentials below 0 MPa was well described by the virtual osmotic potential model. The model was also used to simulate the results of experiments in which seeds were given a single step change in water potential. 相似文献
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The effects of different osmotic stresses (from 0 to –8× 105 Pa) obtained with NaC or polyethylene glycol 6000 solutions on the germination of flax, sesame and onion seeds were investigated. The effect of presoaking with gibberellic acid (GA3) on the germination of the above mentioned seeds was also studied. It was found that the rate of seed germination and the final germination percentages as well as the amount of water absorbed by the seeds were considerably lowered with the rise of osmotic stress levels whatever the stress agent used, more considerable reduction was obtained under polyethylene glycol 6000 than under NaCl. Presoaking with gibberellic acid increased the rate and the final germination percentage of osmotically stressed flax and sesame seeds, while those of stressed onion seeds were slightly retarded. 相似文献
12.
Effects of light, temperature and water stress on germination of Artemisia sphaerocephala 总被引:3,自引:1,他引:3
YUANRUN ZHENG ZHIXIAO XIE YONG GAO LIANHE JIANG XUERONG XING HIDEYUKI SHIMIZU GLYN M RIMMINGTON 《The Annals of applied biology》2005,146(3):327-335
Artemisia sphaerocephala is widely used for vegetation rehabilitation, but its germination is very low after air seeding of achenes. We explored effects of light, temperature and water stress on germination. Results show that both final percent germination and germination rate were increased by temperature increment, with the highest values occurring at 15: 25°C (night: day) in dark and 20: 30°C under light. Light inhibited germination, especially at lower alternating temperatures (5: 15°C and 10: 20°C). The alternating temperature window for germination was slightly narrower under light than in dark, and germination was slower under light than in dark across the temperature range. Achenes incubated in the dark and at constant temperatures had over 80% germination at 10 to 25°C, with an optimum at 20°C. Under dark and 25μmol m‐2 s‐1 light flux density at 10: 20°C, final percent germination was over 94%, but if the light flux density was increased to 100 and 400 μmol m‐2 s‐1, final percent germination was significantly lower (64% and 38% respectively). However, achenes could keep their germination capacity for a long time (over 50 days) and germinate well after going back to the dark. Germination was also lower under water stress and few achenes germinated at ‐1.4 MPa. This was more pronounced at high and low temperatures. Given these findings and the prevailing climatic characteristics, the most suitable time for air seeding of achenes may be mid‐May. 相似文献
13.
Antagonistic effects of high and low temperature pretreatments on the germination and pregermination ethylene synthesis of lettuce seeds 下载免费PDF全文
Burdett AN 《Plant physiology》1972,50(2):201-204
Red light-induced germination of Grand Rapids lettuce seeds (Lactuca sativa L.) incubated at 20 C was inhibited if the seeds were first imbibed at 30 C for 36 hours. This effect was counteracted by exogenous ethylene and associated with a reduction in the rate at which the seeds produced ethylene throughout the pregermination period. A chilling treatment reversed the effect of a prior imbibition at 30 C on both germination and ethylene production. The possibility that the pretreatments influence germination through their effects on ethylene production is discussed. 相似文献
14.
Plant Ecology - Mediterranean shrublands are water-limited and fire-prone ecosystems. Post-fire seed regeneration occurs under a rainfall regime that is highly variable, with frequent drought... 相似文献
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16.
Effect of high temperature and water stress on pollen germination and spikelet fertility in rice 总被引:9,自引:0,他引:9
Z.W. Rang S.V.K. Jagadish Q.M. ZhouP.Q. Craufurd S. Heuer 《Environmental and Experimental Botany》2011,70(1):58-65
In future climates, rice could more frequently be subjected to simultaneous high temperature and water stress during sensitive developmental stages such as flowering. In this study, five rice genotypes were exposed to high temperature, water stress and combined high temperature and water stress during flowering to quantify their response through spikelet fertility. Microscopic analyses revealed significant differences in anther dehiscence between treatments and genotypes, with a moderately high association with the number of germinated pollen grains on the stigma. There was a strong relationship between spikelet fertility and the number of germinated pollen on stigmas. Although, all three stress treatments resulted in spikelet sterility, high-temperature stress caused the highest sterility in all five genotypes. A cumulative linear decline in spikelet fertility with increasing duration of independent high-temperature stress and in combination with water stress was quantified. Better anther dehiscence, higher in vivo pollen germination, and higher spikelet fertility were observed in both the N22 accessions compared with IR64, Apo and Moroberekan under high temperature, water stress and combined stress, indicating its ability to tolerate multiple abiotic stresses. 相似文献
17.
When New York lettuce seeds were imbibed below 20°C in thedark, full germination was observed, whereas none occurred above35°C even under red-light irradiation. Partial treatmentwith high temperature during imbibition revealed the involvementof a thermo-labile process in the germination. This processwas completely inhibited above 30°C in the dark, but re-activatedby the following incubation below 20°C. The longer the seedswere preincubated above 30°C, the longer the period below20°C required for re-activation. The results suggest thatthe thermo-labile process is controlled by a thermo-labile factor.The factor was inactivated slowly at 25°C and rapidly above30°C to a form which could be re-activated below 20°Cbut was irreversibly inactivated when the seeds were imbibedat temperatures above 45°C for more than 40 hr. The escapereaction of the phytochrome system proceeded even at 35°Cwhereas no germination was observed at that temperature. Thus,die germination of lettuce seeds is regulated not only by thephytochrome system but also by the thermolabile factor. (Received August 11, 1975; ) 相似文献
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19.
Naturally and artificially aged seeds of rape, Brassica napus L., produced less ethylene than freshly harvested seed during the early stage of germination. With freshly harvested seeds one peak of ethylene production was observed during germination, which coincided with the emergence and elongation of root and cotyledon, accompanied by splitting of the seed coat. Application of exogenous ethylene was effective in accelerating germination in aged seeds but did not significantly improve the percentage of germination. Ethylene as a hormone was considered to serve as a stimulator of germination and growth. One of the factors causing seed aging might be the degeneration of an ethylene-producing system in the seed. Exogenous ethylene may be effective only for the seeds in which the ethylene-producing system is weakened but the following responding systems are still functional. 相似文献
20.
Effects of temperature, water potential, and light on germination responses of redroot pigweed seeds to ethylene 总被引:2,自引:1,他引:2 下载免费PDF全文
The responses of redroot pigweed (Amaranthus retroflexus L.) seeds to nine ethylene concentrations between 0.5 and 50 microliters per liter were assessed at different temperatures and water potentials and in either continuous white light or darkness. Under all experimental treatments, the probit-transformed percentages increased linearly with the log of the ethylene concentration. In dormant seeds, the slope of the response line was unaffected by either light or water potential but increased with decreasing temperature. Conversely, the slope increased with increasing temperature in a partially afterripened seed lot. 相似文献