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1.
Effect of Salt Stress on Viability, Germination and Endogenous Levels of Some Metabolites and Ions in Maize (Zea mays L.) Pollen 总被引:2,自引:0,他引:2
Maize plants, subjected to 0, 80, 120 and 160 meq l1salinity using NaCl, showed adverse effects on viability, germinationand tube growth of pollen, besides enhancing the bursting ofpollen. The endogenous levels of various metabolites in pollenwere also affected. Pollen grains from salinized plants hadmore soluble carbohydrates, free amino acids, especially proline,phenols and DNA and less starch, protein and RNA compared tothe non-saline controls. Salinity also resulted in the accumulationof ions such as Na+, K+ and Cl while it caused a reductionin the boron content of pollen. These metabolic disturbancespossibly lead to decreased viability, germination and tube growthof pollen thereby resulting into a reduction in reproductivecapacity of the plants under salt stress. Zea mays L., maize, pollen, viability, germination, salt stress 相似文献
2.
Anthers of Hordeum vulgare cv. Sabarlis at the mid-unicellularpollen stage, pretreated in the excised spike for 14 d at 7°C, dehisce within 24 h of being floated on the surfaceof liquid medium. About half the pollen (1500 grains per anther)is liberated into the medium. If the anthers are then removedand the cultures re-incubated, calluses develop from the shedpollen in high yields. At low anther densities, 10p20(13 x 104 grains) per ml, medium preconditioned by anthersand supplemented with m-inositol (1000 mg 11) is required,but at high densities, 120 anthers (2 x 105 grains) per ml,preconditioning is less important, the cultured anthers themselveshaving a sufficient conditioning influence. Large-scale dissectionof anthers can be avoided by use of drops of medium, the volumebeing increased gradually as culture proceeds. Pollen remainingin the anthers after 3 d gives rise to calluses if isolatedmechanically and cultured in the inositol medium. The use ofshed pollen is seen as particularly valuable for culture inspecies whose anthers are small, tedious to dissect out anddifficult to process without severe damage. 相似文献
3.
Incorporation of polyamine-spermidine into the nutrient mediumat 106 and 105 M concentrations stimulates pollen-tubegrowth in vitro in Catharanthus roseus L. G. Don. MGBG, an inhibitorof spermidine biosynthesis, at 0.5 x 103 and 1 x 103M concentrations reduced the percentage of germination as wellas tube growth and at a concentration of 1.5 x 103 Mgermination was totally inhibited. Pollen grains incubated inthe medium containing 1.5 x 103 M MGBG, when transferredto a fresh medium with 105 M spermidine, resulted in80% germination recovery, along with considerable tube growth.Experiments with actinomycin-D indicate that stimulation ofpollen-tube growth by spermidine may involve de novo synthesisof protein. Catharanthus roseus, pollen germination, tube growth, spermidine, MGBG, inhibition, actinomycin-D 相似文献
4.
Brassica oleracea pollen was applied to a basic medium of 1.5per cent agar and 15 per cent sucrose to which flavanoids wereadded at three concentrations. Two types of agar were used;with agar 1, quercetin at a concentration of 0.5 x 103per cent gave an increase in percentage germinating grains.With agar 2, an increase in germination occurred with kaempferoland naringin at concentrations of 0.5 x 103 and 0.5 x101 per cent respectively. Increase in pollen tube lengthoccurred with agar 2 and quercetin at a concentration of 0.5x 103 per cent. The stigma tissue of B. oleracea contains at least three andthe pollen at least one glycoside of quercetin. The sugars inthe glycosides were not identified. Pollen germination and pollentube extension were not stimulated exclusively by the flavanoidspresent in the stigma. The flavanoid composition of the stigmadid not vary amongst five different S-allele genotypes, indicatingthat flavanoids are probably not directly involved in the incompatibilityreaction of B. oleracea. 相似文献
5.
Pine (Pinus roxburghii) pollen grown in suspension cultureswas used to study the effects of growth regulators and lightconditions on germination and pollen tube growth. Indol-3-ylacetic acid, gibberellic acid, ethylene, abscisic acid and cyclicAMP (cAMP) at low concentrations (110 mg 11) promotedgermination and tube growth. Addition of 1 and 10 mg 11cAMP to any of the growth regulators had a promotory effect.Pollen tube growth decreased in white light as compared to thedark, and was increased in red light. Far-red light counteractedthe effect of red light. The effect of growth regulators incausing the enhanced tube growth appears to be manifested throughsubstances such as cAMP, and phytochrome seems to be involved. Pinus roxburghii, pine, pollen germination, pollen tube growth, growth regulators, cyclic AMP, phytochrome 相似文献
6.
The Effect of Brassica oleracea Stigma Extracts on the Germination of B. oleracea Pollen in a Thin Layer Chromatographic Bioassay 总被引:1,自引:0,他引:1
Hodgkin, T. and Lyon, G. D 1986. The effect of Brassica oleraceastigma extracts on the germination of B. oleracea pollen ina thin layer chromatographic bioassay.J. exp. Bot. 37:406411. A procedure for germinating Brassica oleracea pollen on thinlayer chromatography plates pretreated with 20 mol m3tris(hydroxymethyl) methyl-aminopropanesulphonic acid (TAPS)buffer, pH 8·0 has been devised and used to detect pollengermination inhibitors in B. oleracea stigma extracts. Inhibitory zones in extracts of stigmas, unpollinated, or collected0·5, 4, 8 and 24 h after self- or cross-pollination,differed little in RF values and sizes. Extracts of stigmascollected 1 h and 2 h after self-pollination gave a small additionalinhibitory zone which was not detected in 1 h and 2 h cross-pollinatedstigma extracts. The results showed some differences from thoseobtained using Petunia hybrida pollen germinated on T.L.C. platesthat were not pretreated with buffer. The nature of the differencesbetween the two bioassays is discussed and some possible reasonsfor them indicated. Key words: Pollen, germination inhibitors, self-incompatibility, Brassica oleracea 相似文献
7.
Induction and Growth of 'Microspore-Derived' Embryos of Brassica napus ssp. oleifera 总被引:2,自引:0,他引:2
DUNWELL J. M.; CORNISH M.; DE COURCEL A. G. L.; MIDDLEFELL-WILLIAMS J. E. 《Journal of experimental botany》1983,34(12):1768-1778
Three cultivars of spring rape (Brassica napus ssp. oleifera),Tower, Willi and Duplo, were used for a study of induction andgrowth of microspore-derived embryos, Buds, 2.0mm in length, containing uninucleate microspores were harvestedand stored for 14 d at 4 ?C in darkness. Anthers were then removedand cultured on a liquid medium based upon that of Murashigeand Skoog and containing 8% sucrose, 0.5 mg l1 naphthylaceticacid and 0.05 mg l1 benzylaminopurine. Cultures werepre-incubated at 35 ?C for 03 d and then incubated at30 ?C. After a total of 42 d incubation, cultures were scoredfor the presence of macroscopic embryos (12 mm in length)and for the presence of anthers containing abortive embryoidswhich had not developed further. The cultivars differed greatly in terms both of the frequencyof anthers showing induced embryoids and of the final yieldof embryos. Tower showed the highest frequency of induction(maximum 38% of cultured anthers with induced embryoids) whereasthe highest yield (equivalent to 1.1 embryo per cultured anther)was obtained from anthers of the cv. Duplo after a 3 d treatmentat 35 ?C. Yields from the other cultivars were much lower andwere relatively unaffected by the 35 ?C treatment. Key words: Brassica napus, Rape, Anther culture, Pollen, Haploid 相似文献
8.
The influence of salinity in the growing media on ribulose-1,5-bisphosphate (RuBP) carboxylase and on CO2 fixation by intactsugar beet (Beta vulgaris) leaves was investigated. RuBP carboxylase activity was mostly stimulated in young leavesafter exposure of plants for 1 week to 180 mM NaCl in the nutrientsolution. This stimulation was more effective at the higherNaHCO2 concentrations in the reaction medium. Salinity also enhanced CO2 fixation in intact leaves mostlyat rate-limiting light intensities. A 60 per cent stimulationin CO2 fixation rate was obtained by salinity under 450 µEm2 s1. At quantum flux densities of 150 µEm2 s1 (400700 nm) this stimulation was280 per cent. Under high light intensities no stimulation bysalinity was found. In contrast, water stress achieved by directleaf desiccation or by polyethylene glycol inhibited enzymeactivity up to fourfold at 1.2 MPa. Beta vulgaris, sugar beet, ribulose-1, 5-bisphosphate carboxylase, salt stress, water stress, carbon dixoide fixation, salinity 相似文献
9.
An attempt has been made to separate the osmotic effect fromthe ionic effect of KCI in stomatal responses. For this purposeisolated illuminated epidermis from species with and withoutsubsidiary cells were treated with KCI (0-250 mOs kg1)and with mannitol (0-250 mOs kg1). Since osmolarity wasmade the basis of comparison, the effect of mannitol had tobe observed immediately, before guard cell contents could haveleached into the incubation medium. When plotting aperturesagainst osmolarity sigmoid curves were obtained with KCI, butwith mannitol straight lines resulted provided that prior tostripping and incubation leaves were briefly illuminated. Whilst in lower concentrations (60 mOs kg1 for Viciafaba; 90 mOs kg1 for Zantedeschia aethiopica; 190 mOskg1 for Commelina communis) pores were wider in mannitolthan in KCI, in concentrations above these values the situationwas reversed. It appeared therefore that KCI had either an inhibitoryor a promoting effect. Inhibition was most pronounced when atthe beginning of incubation stomata were closed; the inhibitoryeffect on stomata without subsidiary cells occurred at low concentrations(0-60 mOs kg1) whereas when subsidiary cells were presentinhibition occurred at up to 190mOs kg1. Other experiments started with KCI solutions of 50 mOs kg1for Vicia faba, 85 mOs kg1 for Zantedeschia aethiopicaand 115 mOs kg1 for Commelina communism; mannitol wasadditionally used to give the progressive increases in osmolarity.Degrees of opening were then reached which with KCI alone couldonly be attained at the very highest concentrations. Starch disappearance was followed using the periodic-acid-silvertest; by using either 86Rb or 43K it was shown that ion uptakewas restricted to guard cells alone only at osmolarities exceeding200 mOs kg1. On the basis of these observations it was concluded that K transportdoes not represent the major mechanism of stomatal regulation. Key words: Stomata, Potassium, Osmolarity 相似文献
10.
Effect of Salinity on Growth, Nodulation and Nitrogen Yield of Chickpea (Cicer arietinum L.) 总被引:2,自引:0,他引:2
Chickpea cultivar ILC 482 was inoculated with salt-tolerantRhizobium strain Ch191 in solution culture with different saltconcentrations added either immediately with inoculation or5 d later. The inhibitory effect of salinity on nodulation ofchickpea occurred at 40 dS m1 (34.2 mol m3 NaCl)and nodulation was completely inhibited at 7 dS m1 (61.6mol m3 NaCl); the plants died at 8 dS m1 (71.8mol m3 NaCl). Chickpea cultivar ILC 482 inoculated with Rhizobium strain Ch191spcstrwas grown in two pot experiments and irrigated with saline water.Salinity (NaCl equivalent to 14 dS m1) significantlydecreased shoot and root dry weight, total nodule number perplant, nodule weight and average nodule weight. The resultsindicate that Rhizobium strain Ch191 forms an infective andeffective symbiosis with chickpea under saline and non-salineconditions; this legume was more salt-sensitive compared tothe rhizobia, the roots were more sensitive than the shoots,and N2 fixation was more sensitive to salinity than plant growth. Key words: Cicer arietinum, nodulation, N2 fixation, Rhizobium, salinity 相似文献
11.
Activities of CaMV 35S and nos promoters in pollen: implications for field release of transgenic plants 总被引:7,自引:1,他引:6
The expression of foreign genes in pollen may pose potentialproblems in the field release of transgenic plants, since pollenrepresents a route whereby foreign genes and their productsmay escape into the wider environment. The possible risks posedby cross-hybridization with wild relatives have been extensivelyexplored, but problems that may arise due to the expressionof foreign gene products in pollen have not been so widely studied.The activities of the CaMV 35S and nos promoters in pollen inpopulations of stably transformed plants and in transient expressionanalysis are described. These promoters are commonly used inall areas of plant molecular biology research and their expressionpatterns will be of interest to those involved in field releasestudies. The results show that both promoters had no detectablepollen activity in Arabidopsis, but both showed activity intobacco pollen. The CaMV 35S-gus gene fusion showed heritableexpression levels in tobacco pollen of up to a maximum of 64.6pmol 4-MU min1 mg 1 total protein. nos promoteractivity in transgenic tobacco pollen was highly variable, withGUS activities ranging from undetectable levels up to 2561 pmol4-MU min1 mg1 total protein within the transgenicpopulation. Histochemical staining of anther sections from 1012mm buds revealed that the CaMV 35S promoter had some activityin the vascular bundle, stomium and tapetum, while GUS expressionfrom the nos promoter in sporophytic tissues was confined entirelyto the stomium. Key words: CaMV 35S promoter, nos promoter, pollen, transgenic plant release 相似文献
12.
Chlorophyll (Chl) a was measured every 10 m from 0 to 150 min the Transition Domain (TD), located between 37 and 45°N,and from 160°E to 160°W, in May and June (Leg 1) andin June and July (Leg 2), 199396. Total Chl a standingstocks integrated from 0 to 150 m were mostly within the rangeof 20 and 50 mg m2. High standing stocks (>50 mg m2)were generally observed westof 180°, with the exceptionof the sporadic high values at the easternmost station. Thetotal Chl a standing stock tended to be higher in the westernTD (160°E172°30'E) than in the central (175°E175°W)and eastern (170°W160°W) TD on Leg 1, but thesame result was not observed on Leg 2. It was likely that largephytoplankton (210 and >10 µm fractions) contributedto the high total Chl a standing stock. We suggest that thehigh total Chl a standing stock on Leg 1, in late spring andearly summer, reflects the contribution of the spring bloomin the subarctic region of the northwestern Pacific Ocean. Thedistribution of total Chl a standing stock on Leg 2 was scarcelyaffected by the spring phytoplankton bloom, suggesting thattotal Chl a standing stock is basically nearly uniform in theTD in spring and summer. Moreover, year-to-year variation inthe total Chl a standing stock was observed in the western TDon Leg 1, suggesting that phytoplankton productivity and/orthe timing of the main period of the bloom exhibits interannualvariations. 相似文献
13.
Tobacco shoots were grown in vitro for 35 d, in MS culture mediummodified to include various sources (nitrate-N, ammonium-N ora mixture) and levels (0120 mM) of N, and in the presenceof 0180 mM NaCI or iso-osmotic concentrations of mannitol.Growth of control plantlets was significantly inhibited whenNH4+-N was the sole N source, and at high (120 mM) NO3-N supply. Under conditions of salt stress (90 and 180 mM NaCI)growth was repressed, with roots being more severely affectedthan shoots. Salinity also inhibited root emergence in vitro.The only alleviation of the salt stress by nitrate nutritionobserved in this study was on shoot growth parameters of plantletsgrown on 60 mM NO3-N and 90 mM NaCI. Although both weresignificantly inhibited by NaCI, nitrate reduc-tase activitywas more severely affected than nitrate uptake. When mannitolreplaced NaCI in the culture medium, similar Inhibition of growth,nutrient uptake and enzyme activity were recorded. These observations,together with the relatively low recorded values for Na+ andCI uptake, indicate that under in vitro salt stress conditionsthe negative effects of NaCI are primarily osmotic. Key words: Growth, nitrogen metabolism, osmotic stress, salinity 相似文献
14.
Feeding of planktonic rotifers on ciliates: a method using natural ciliate assemblages labelled with fluorescent microparticles 总被引:1,自引:0,他引:1
Joaquim-Justo Celia; Detry Cedric; Caufman Fabrice; Thome Jean-Pierre 《Journal of plankton research》2004,26(11):1289-1299
A method was developed to allow direct measurements of predationexerted by metazooplankton on ciliates. The method relied onthe use of ciliates labelled with fluorescent microparticles(FMP). Optimal labelling conditions were determined with ciliatesfrom cultures (Tetrahymena pyriformis) and with natural ciliateassemblages sampled in a river. Labelled T. pyriformis wereused as tracer food to determine gut passage time (GPT) andingestion rates of the rotifer Brachionus calyciflorus in thelaboratory. Predation of metazooplankton from the lowland riverMeuse (Belgium) was determined by labelling natural assemblagesof ciliates and using them as tracer food for metazooplankterssampled in the river. Optimal labels of ciliates, i.e. sharpdistribution of FMP in cells, were obtained with short incubations(10 min) and low FMP concentrations (1 x 105 mL1). GPTvaried between 30 and 45 min for B. calyciflorus and from 25up to >35 min for rotifers from the river. The ingestionrate of B. calyciflorus fed with T. pyriformis was 3.3 ±0.6 ciliate rot1 h1, i.e. 1.4 ± 0.3 ngCrot1 h1. Metazooplankton species for which theingestion of ciliates could be measured were the rotifers Keratellacochlearis, Euchlanis dilatata and Synchaeta spp. Ingestionrates measured ranged from 0.4 to 12.5 ngC rot1 h1.The method proposed proved to be useful in estimating the predationof microplankton on ciliates in semi- in situ conditions; infurther developments, labelled natural assemblages of ciliatescould be used for in situ incubations with the Haney chamber. 相似文献
15.
Callus of sainfoin (Onobrychis viciifolia Scop.) was initiatedfrom stem and root explants which were obtained from seedlingsgrowing in vitro, on Linsmaier Skoog (LS) medium supplementedwith 1 mg l1 2, 4-D and 1 mg l1 BA or only 1 mgl1 BA, and the Vacin and Went medium without hormones.Somatic embryos were formed on LS medium containing 1 m l1BA. Embryos developed into complete plants on filter paper saturatedwith hormone-free LS medium. Onobrychis viciifolia, somatic embryogenesis, callus culture, plant regeneration 相似文献
16.
The treatment of potato tubers with 150 µmol dm3gibberellic acid (GA3) stimulated starch breakdown and hexoseaccumulation in tuber tissues and the transfer of dry matterto stems. These effects could not be accounted for by enhancedactivities of starch phosphorylase, amylase and acid invertase.Indeed enzyme activities either declined or remained relativelyconstant as starch degradation and hexose accumulation proceeded.Changes in the rate of starch depletion were related to changesin sink strength and sink type, the onset of tuber initiationin controls causing the rate of starch degradation to exceedthat in GA3-treated tissues, in which tuberization was inhibited. Solanum tuberosum L., gibberellic acid, starch breakdown 相似文献
17.
Phytoplankton rate processes in the oligotrophic waters of the central North Pacific Ocean 总被引:1,自引:0,他引:1
Sharp Jonathan H.; Perry M.J.; Renger Edward H.; Eppley Richard W. 《Journal of plankton research》1980,2(4):335-353
The central North Pacific is one of the more oligotrophic regionsof the world oceans. There the particulate organic nitrogen:cabonratio of surface waters is variable and less than the Redfieldratio of 16N:106C by atoms. The phytoplankton P/B ratio basedupon both C and N assimilation rate varied directly with theparticulate matter PON:POC ratio as did the productivity index[mg C (mg chl a)1h1]. At steady state the doublingtime of the phytoplankton, the turnover time of the limitingnutrient supplied via herbivore grazing, and the time for herbivoresto filter a unit volume of water would be equivalent. They appearto be of the order of 59 days based on present methodologyand straightforward interpretation of its results. The rate measurements involved incubation of water samples forseveral hours in bottles. In the central N. Pacific the valueswere similar using bottles of different sizes. Addition of chelatorsdid not enhance the rates implying no poisoning of the planktonby heavy metal contaminants. The observed specific activitiesof 14C and 15N of the particulate matter in the rate measurementsare inconsistent with the notion of an active, rapidly growingand recycling microplankton food web within the incubation bottlesand support the idea that phytoplankton are growing slowly. 相似文献
18.
To find whether cytoplasmic streaming in Acetabularia is controlledby Ca2+, a tonoplast-permeabilized cell model was prepared usinga vacuolar perfusion technique. The cytoplasmic streaming remainedalmost normal after perfusion with EGTA medium (10 mM EGTA,40 mM PIPES, 5mM MgCl2 and 800 mM sorbitol, pH 6.9), but stoppedwithin 10 min when saponin medium (EGTA medium plus 50 µg/mlsaponin, 50 µg/ml hexokinase and 5 mM glucose) was perfused.This model system was reactivated with a solution containing0.5 mM ATP and different concentrations of Ca2+ (reactivationmedium). With the reactivation medium at pCa 65, theresumed streaming lasted for about 10 min before the cytoplasmaggregated. At pCa 43, the streaming was observed onlyfor a few minutes because the cytoplasm aggregated quickly.At pCa 7, no reactivated movement was observed. Reactivationwas not induced in an ATP- or Mg2+-deficient medium even inthe presence of an adequate concentration of Ca2+, and was inhibitedby 50 µg/ml cytochalasin B or 1 mM N-ethylmaleimide. We concluded from these observations that the cytoplasmic streamingin Acetabularia is very likely to be driven by the actomyosinsystem in the presence of Mg-ATP and Ca2+ at pCa 65. (Received October 31, 1984; Accepted April 1, 1985) 相似文献
19.
Cyst formation: an important mechanism for the termination of Scrippsiella trochoidea (Dinophyceae) bloom 总被引:1,自引:0,他引:1
A sediment trap study was conducted at Daya Bay, South ChinaSea, to investigate the relationships between encystment andpopulation dynamics of Scrippsiella trochoidea from December1999 to January 2001. A dense bloom of S. trochoidea occurredduring the study period from August to September 2000, withthe maximum cell number of 3.18 x 104 cells mL1.Two morphotypes of cysts, one with a thick calcareous wall (calcifiedcyst) and another without the obvious calcareous cover (non-calcifiedcyst), were observed during this investigation. The morphologicaland excystment characteristics of these two cyst types werestudied as well. Mass encystments of S. trochoidea, with themaximum of 3.05 x 105 cysts m2 d1for calcified cyst, and 1.54 x 107 cysts m2 d1for non-calcified cyst, coincided with the maximum abundanceof the vegetative cells. Encystment caused the transfer of atotal of 2.244.49 x 108 cells m2 vegetativecells from the water column to the sea bottom during the bloomand resulted in a considerable loss of the bloom population.High assemblages of cysts of S. trochoidea were detected inthe surface sediments as well. This rich seed bedin the surface sediments caused by the high efficiency of encystmentafter blooms acting as a benthic reservoir for future vegetativepopulation, together with the short dormant period (1526days) and high germination rate (5090%), may explainthe repeated occurrence of S. trochoidea blooms in Daya Bay. 相似文献
20.
Callus and suspension cultures of Theobroma cacao L., initiatedfrom immature cotyledons of beans from pods harvested 120130days after pollination were established. A modified B-5 or MurashigeSkoogagar medium sustained growth of callus without loss of vigourafter each sub-culture. A 15-fold weight increase occurred duringthe 4 week culture periods at 30 ± 1 °C. Coconutwater improved callus growth substantially. The optimum hormonalconcentrations for growth of suspensions were 0.5 mg 11of 2, 4-dichlorophenoxyacetic acid and 0.1 mg I1 of kinetinin a MurashigeSkoog basal medium liquid medium. The optimumtemperature for growth of suspensions was 2530 °C.The cell number and cell mass of suspensions increased 20-foldin 14 days. No organogenesis or embryogenesis was observed. Theobroma cacao L., acao, cell culture, suspension culture, tissue culture. 相似文献