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1.
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
2.
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
3.
Guttation was used as a non-destructive way to study the flowof water and mineral ions from the roots and compared with parallelmeasurements of root exudation. Guttation of the leaves of barley seedlings depends on age andon the culture solution. Best rates of guttation were obtainedwith the primary leaves of 6- to 7-day-old seedlings grown onfull mineral nutrient solution. The growing leaf tissue becomessaturated with K+ below 1.5 mM K+ in the medium, whereas K+concentration in the guttated fluid still increases furtheras K+ concentration in the medium is raised. At 3 mM K+ averagevalues of guttation were 1.42.4 mm3 h1 per plantwith a K+ concentration of 1020 mM; for exuding plantsthe flow was 4.27.6 mm3 h1 per plant and K+ concentration3555 mM. Abscisic acid (ABA) at 106 to 104 M 02h after addition to the root medium increased volume flow ofguttation and exudation and the amount of K+ exported. Threeh after addition of ABA both volume and amount of K+ were reduced.There was an ABA-dependent increase in water permeability (Lp)of exuding roots shortly after ABA addition. Later Lp was decreasedby 35 per cent and salt export by 60 per cent suggesting aneffect of ABA on salt transport to the xylem apart from itseffect on Lp. Benzyladenine (5 x 108 to 105 M)and kinetin (5 x 106 M) progressively reduced volumeflow and K+ export in guttation and exudation and reduced Lp. Guttation showed a qualitatively similar response to phytohormonesas found here and elsewhere using exuding roots. Hordeum vulgare L., barley, guttation, abscisic acid, cytokinins, benzyl adenine, kinetin 相似文献
4.
The kinetics of 14C-2-acetate assimilation by Chlorella pyrenoidosain the light were examined. Under aerobic conditions the primaryproduct of acetate assimilation was succinic acid which, afterten seconds, contained over 60 per cent of the 14C incorporatedby the cells. The percentage of the total 14C in succinate fellwith time, while that in citrate and glutamate increased. After1800 sec over 60 per cent of 14C was present in two compounds,glutamic acid and an unknown compound (X). Glucose-6-phosphate,fructose-6-phosphate, phosphoglyceric acid and phosphoenolpyruvicacid became labelled after 60 sec but together never containedmore than one per cent of the total 14C incorporated. Underanaerobic conditions succinate was still the primary productof acetate assimilation, and the absence of carbon dioxide resultedin a decrease in 14C incorporation into compound X. The patternof acetate assimilation in acetate grown and acetate adaptedChlorella was very similar to that in photo-autotrophicallygrown Chlorella. In the presence of 106M DCMU, succinicacid was the primary product of acetate assimilation, but therewas an early Incorporation of 14C into glutamate, aspartate,and malate. 4 x103M MFA did not effect the early incorporationof 14C into succinic acid, but resulted in accumulation of 14Cin citrate and a decreased amount in glutamate and in compound X. 相似文献
5.
Germination of akinetes of Anabeana vaginicola v. fertilissimaPrasad in response to environmental stress was studied. Additionof nitrate to the medium induced early and maximum germination(96 per cent), whereas less than half of the akinetes germinatedwhen either nitrate or phosphate was omitted from the medium.The pH range over which germination occurred was 7.09.0.The desiccated akinetes after rehydration germinated after acertain lag period, depending upon the dehydration state. Thetemperature optimum for germination and vegetative growth wasthe same (25 °C) and germination did not occur at 5 °Cor above 35 °C. The limit of heat shock tolerated was 55°C for 4 min. In addition to white light, only the red partof the visible spectrum induced germination. Ultraviolet radiationreduced germination rate presumably by inducing thymine dimersin DNA. The photoreactivating system (s) in akinetes is certainlynon-photosynthetic. LD50 photon flux densities were 300 Jm2for akinetes and 240 Jm2 for vegetative cells. Anabaena vaginicola, blue-green alga, akinete, germination, environmental stress 相似文献
6.
Three-month old and fresh seedsof Talinum triangulare were subjected to various treatmentsto induce early and rapid germination. Scarification and activated carbon were the most effective treatmentsin improving total germination in fresh seeds, while the 3 and5 per cent thiourea treatments were most effective in improvingtotal germination in old seeds. Activated carbon, scarificationand 5 per cent thiourea treatments enhanced early germinationin both old and fresh seeds. Cumulative percentage germinationwas very high in fresh seeds after scarification or after treatmentwith activated carbon and 5 per cent thiourea, and lowest inseeds treated with 3 per cent thiourea and hot water. In oldseeds, highest cumulative percentage germination was obtainedwith 3 and 5 per cent thiourea treatments and scarification.Generally, higher germination was obtained with fresh seedsthan with old seeds. Partial seed-coat removal and treatment with 5 per cent thiouriaresulted in a higher rate of and cumulative percentage germinationcompared with seeds with the coat partially removed but nottreated with thiourea. Constantly high temperature (34 °C) increased both rateand total germination compared with seeds planted at room temperature(2023 °C). Treatments that did not induce germinationwere 1 per cent thiourea, H2SO4, cold water soaking at roomtemperature, 6 per cent hydrogen peroxide and soil planting.These treatments effected less than 3 per cent germination. Talinum triangulare L, seed scarification, activated charcoal, thiourea, germination 相似文献
7.
Cylinders of pith of Nicotiana tabacum var. Wis. 38 were asepticallyisolated and grown on a mineral-sucrose medium in the presenceand absence of either kinetin or zeatin. On medium containing kinetin (5x106M) the increase in the residualdry weight of cylinders was greater than that on control mediumafter 2 d culture and this was maintained at 5 d. At 2, 5, and7 d there were increments in the DNA and RNA levels of cylindersdue to kinetin treatment and these increased progressively. A double-labelling method coupled with acrylamide gel electrophoresiswas used to study the effects of kinetin at 5 x 106Mand zeatin at 106 M on the incorporation of radioactiveprecursors into the RNA of cylinders given a 4-h label pulse.No effects of zeatin were observed after 1 d nor of kinetinat 2 d but after 4 d zeatin stimulated incorporation into ribosomal,transfer and poly-disperse RNA and kinetin did likewise after5 d. Incorporation measured at 7 d was reduced in cylindersfrom which kinetin had been removed at 5 d compared to thoseto which it had been supplied continuously. Scans at 260 run of the electrophoretic fractionations of RNAafter 2, 5, 7, and 9 d of culture showed that both in the absenceand in the presence of kinetin the proportion of 4S RNA increasedfrom about 20 per cent to over 50 per cent of the total between2 and 5 d of culture and after 5 d the ribosomal RNA gave aberrantscans apparently indicative of degradation. These aberrant scanspersisted in RNA extracted after 27 d culture in both the presenceand absence of kinetin. 相似文献
8.
Very few sporangia of Phytophthora palmivora germinated directlyand produced secondary sporangia in distilled water and in solutionsof amino acids and carbohydrates at 30 °C. Although 1.0per cent (w / v) peptone and yeast-extract stimulated a highpercentage of germination by formation of germ tubes, less than1.0 per cent of the germinated sporangia produced secondarysporangia. Secondary sporangium formation was induced by transferringgerminated primary sporangia from a nutrient medium of sufficientlyhigh concentration to either distilled water or dilute solutionsof organic and inorganic compounds immediately after emergenceof the germ tubes. The percentage of germinated sporangia formingsecondary sporangia was influenced by both the nature and concentrationof the medium into which they were transferred. The secondarysporangia were significantly smaller than the primary sporangia. Phytophthora palmivora, germination, sporangium, Theobroma cacao L., cocoa 相似文献
9.
Long-term Partitioning, Storage and Re-mobilization of 14C Assimilated by Lolium perenne (cv. Melle)
The youngest fully expanded leaves of single tillers of vegetativeperennial ryegrass plants were exposed to 14CO2. Thereafter,quantitative and fractional analysis of the partitioning, storageand re-mobilization after defoliation of the 14C-labelled assimilatewas sequentially conducted over a 22 d period. In undefoliated plants, most 14C reached its final destinationwithin 56 of feeding. Forty per cent of assimilated 14Cwas subsequently lost through respiration, while 13.5, 8.5 and34 per cent remained in roots, stem bases and tops respectively.At least some 14C was distributed to tillers throughout theplant, but secondary tillers subtended by the fed tiller madethe greatest demand on 14C translocated from the fed tiller. A small, but significant portion of 14C was invested into longterm storage in undefoliated plants, four per cent of the totalassimilated still being present in a labile chemical form inroots and stem bases 22 d after feeding. In plants that wereseverely defoliated 4 d after feeding, depletion of reserve14C was observed relative to undefoliated plants. The depletiontook place from stem bases, not roots, and both low and highmolecular weight storage compounds were involved. A portionof the depleted 14C was incorporated into new growth after defoliation. Lolium perenne, perennial ryegrass, assimilate partitioning, storage, re-mobilization, defoliation 相似文献
10.
A method suitable for the large-scale isolation of cereal protoplastsfrom up to 50 g of leaf material is described. Surface-sterilizedleaves from cultivars of wheat, barley, maize, sorghum, andTriticale were diced and vacuum infiltrated with enzyme mixturecomposed of cellulysin (1 per cent w/v), hemicellulase (1 percent w/v), and macerozyme (0.5 per cent w/v). With this procedure,yields of between 106 to 107 protoplasts per gram of leavescan be reproducibly obtained after only 1.53 h of enzymatictreatment. These protoplasts were almost 100 per cent viable(as determined by fluorescein diacetate staining) and incorporationof 3H-uridine and 14C-leucine into an acid-insoluble fractionwas demonstrated. Almost one-third of the ribosomes of theseisolated protoplasts were present as polysomes. cereals, leaf mesophyll, protoplast isolation 相似文献
11.
The effect of morphactin (methyl 2-chloro-9-hydroxyfluorene-9-carboxylate)on basipetal transport of auxin (Indol-3-ylacetic acid-2-14C)was studied in bean (Phaseolus vulgaris) hypocotyl with thedonor-receiver block method. Morphactin (5 x 106m) reduced IAA (5 x 106m) transportintensity by an average of 83 per cent and auxin transport capacityby 90 per cent, but transport velocity was not affected. Morphactin did not inhibit uptake of IAA into hypocotyl tissue,but it did prevent transfer of IAA from the tissue into receiverblocks. Chromatographic analysis of the tissue after 4 h IAA-2-14Ctransport showed that 54 per cent of the total activity wasin the form of IAA in the control and 42 per cent in the morphactintreated tissue. No difference was found in the rate of decarboxylationof IAA-1-14C between control and morphactin treated tissue sections.Nor could any difference between control and morphactin be shownin the radioactivity associated with a TCA ppt fraction. Ina study of the transportable auxin pool, morphactin decreasedthe size of the pool and increased the half-life of decay ofauxin transport from 122 h to 385 h. In a kineticanalysis of the reversal of morphactin (5 x 106m) inhibitionby increasing concentration of IAA-2-14C (5 x 106m to2 x 105m), it was shown that IAA transport resemblesMichaelis-Menten enzyme reaction kinetics, and that inhibitionby morphactin fitted a mixed type model. IAA hada dissociation constant of 85 x 106m and morphactinthat of 43 x 107m with a Km for the transport processof 85 x 106m. 相似文献
12.
The Effect of Desiccation on the Longevity of Seeds of Araucaria hunsteinii and A. cunninghamii 总被引:1,自引:0,他引:1
Seeds of Araucaria hunsteinii K. Schum. dried quicker at 29°Cthan at 19°C and quicker with the seed-coat removed thanwhen intact; seeds enclosed in polyethylene bags increased inmoisture content. At 15°C, seeds in a flow of air driedquicker than seeds in a box with silica gel, which in turn driedquicker than seeds in a box with no desiccant. No loss of germinationability occurred on drying fresh seed from 53 to about 32 percent moisture content (fresh weight basis); during further desiccationthe percentage germination was related to percentage moisturecontent in the form of a sigmoid curve, culminating in a completefailure to germinate at approximately 14 per cent moisture content.A consistent relationship was observed for all treatments andthe mean critical moisture content for seed death (failure togerminate) was near 23 per cent. Excised embryos grew on 1 percent agar but died if previously subjected to 14 h of desiccationat 15°C. In contrast, no relationship was found between germination andmoisture content of A. cunninghamii D. Don on desiccation from21 to 7 per cent moisture content. Possible causes for the observeddifference in response to desiccation are discussed and methodsfor seed storage are considered. Araucaria hunsteinii, Klinkii pine, Araucaria cunninghamii, Hoop pine, desiccation, seed longevity, storage of seeds 相似文献
13.
The inactivation of nitrate reductase in the leaves and rootsof barley (Hordeum vulgare L. cv. Mazurka) during and afterextracting was investigated. At 0 °C in the absence of casein,25 per cent of total. i.e. maximal in vitro, nitratereductase activity was lost during the 2 min extraction process,followed by a slower loss of activity while the extract wasstored in ice. Activity was maintained by adding a minimum of1 per cent casein to the extraction medium containing 0·1M phosphate (pH 7·5), 1 mM EDTA and 1 mM dithiothreitol.Nitrate reductase was stable for several hours in these extracts,but declined in a first order manner in the absence of dithiothreitol.Casein also prevented the initial loss while making root extracts,but had less effect during storage. Using casein and thiols, nitrate reductase activity in light,(as product of maximal in vitro rates and wt g1) in leaveswas 98 per cent of the total activity in 31-day-old plants grownwith full nutrient in water culture and 60-day-old field-grownplants receiving no fertilizer. Field-grown plants, however,exhibited only 17 per cent of the activity of culture-grownplants. Nitrate reductase in leaves of barley plants grown in waterculture had a diurnal rhythm. During the first 3 h of the lightperiod, activity increased to 1·3 x the darkvalue. This was followed by a temporary decrease and then byanother increase to a maximum of 1·7 x the darkvalue, occurring about 8 h after illumination. Activity thendecreased during the rest of the light period and in darkness. Hordeum vulgare L., barley, nitrate reductase 相似文献
14.
Embryogenic cell suspension cultures were established from calliderived from young leaves of sugarcane (Saccharum officinarumL.) by placing them in liquid medium containing 5 per cent coconutwater (CW), 23 mg 11 2, 4-D and 500 mg 11casein hydrolysate (CH). The cultures were maintained by transferring2.55.0 ml of the suspension to 35 ml of fresh mediumevery 45 days. Organized structures resembling the earlystages of embryogeny were formed when 2, 4-D in the medium waslowered (0.11.0 mg 11) but these did not developbeyond the globular or early scutellar stages. High levels ofsucrose (610 per cent) promoted the formation of proembryoids.Plating of the suspension on MS agar medium supplemented with0.252.0 mg 11 2, 4-D, 5 per cent CW, 500 mg 11CH, with or without activated charcoal, resulted in the formationof embryogenic calli. A large number of embryoids were formedin media containing lower 2, 4-D concentrations. Transfer ofembryoids to half-strength MS medium with 6 per cent sucroseestablished plantlets which were successfully transferred tosoil. Saccharum officinarumL, sugarcane, suspension culture, embryogenesis, regeneration 相似文献
15.
The crop growth rates and structures of three temperate foragegrasses Lolium perenne cv. S24, L. perenne cv. Reveille andFestuca arundinacea cv. S170, were examined in the field duringa summer growth period. The growth rates of the varieties wereremarkably similar at 7 g DM m2 day1. The angularstructures of the varieties were different and they varied duringthe experiment. However, these differences did not seem to affectcrop growth rates. Nevertheless, a decrease in the efficiencyof light energy conversion of approximately 24 per cent wasobserved after a change to a more prostrate form of canopy dueto lodging. There appeared to be an inverse relationship betweenthe number of tillers per unit ground area and the weight ofan individual stem. There were large numbers of relatively lighttillers in S24 whereas S1 70 had fewer but heavier tillers.Furthermore, S24 had many small leaves per unit ground areacompared with SI70 which had fewer longer leaves per groundarea and a slower rate of leaf appearance. There were diurnalchanges in the rates of leaf extension for all the varieties.The mean daily extension rates declined as the canopies developed. 相似文献
16.
The radish varieties Cherry Belle and Long White Icicle wereused to investigate the role of the shoot and the effects ofsynthetic growth promoters in controlling cambial activity inthe seedling axis. Development was compared in excised roots, roots with hypocotylsattached and intact seedlings cultured aseptically on a nutrientmedium. No cambial divisions were seen in isolated radicleswhich had been cultured for ten days following excision butretention of hypocotyl tissue or the entire shoot resulted incambial activity and the production of secondary vascular tissues.Enriching the culture medium by raising the sucrose conantrationto 8% and including 105 M indol-3yl acetic acid (IAA)5 x 106 M 6-benzylaminopurine (BA) and 5 x 104Minositol enhanced root thickening, increasing stele and xylemdiameters in roots cultured both with and without attached shoottissues. The effects of shoot tissues and enrichment of themedium were additive. The effects of auxin, cytokinin and gibberellin (gibberellicacid, GA2) were also studied on daxpitated seedlings. BA wasmuch more effective in inducing cell divisions in the hypocotylthan either IAA or GA supplied separately but a mixture of IAA+GAalso produced clearly defined arcs of cambial tissue. Littlesecondary tissue had been produced after seven days' treatment,and stelar enlargement was due to the development of a cambialzone and cell expansion in the primary tissues. Only minor differencesin response were observed between the two varieties. No stimulation of storage organ development occurred when auxin,cytokinin or inositol was inwrporated into the inorganic culturesolution in which plants of Cherry Belle were grown. Rnphanus sarivus, radish, storage organ, cambial activity, growth promoters, indol-3-ylacetic acid, 6-benzylaminopurine, gibberellic acid 相似文献
17.
Under submerged conditions the germination of maize seeds isinhibited. Under normal conditions, i.e. on moist filter paper,more than 80 per cent of the seeds can germinate whereas lessthan 24 per cent of the seeds germinate under submerged conditions.The inhibition of germination under submerged conditions canbe fully overcome by the application of an appropriate concentrationof GA2, and KN. The possible role of these hormones in overcomingthe inhibition of seed germination under an oxygen deficit dueto waterlogging is discussed. Zea mays L, maize, gibberellic acid, kinetin, germination 相似文献
18.
Soya Bean Seed Growth and Maturation In vitro without Pods 总被引:2,自引:0,他引:2
OBENDORF R. L.; TIMPO E. E.; BYRNE M. C.; TOAI T. V.; RYTKO G. T.; HSU F. C.; ANDERSON B. G. 《Annals of botany》1984,53(6):853-863
Immature Glycine max (L.) Merrill seeds, initially between 50and 450 mg f. wt, were grown and matured successfully in vitro.Excised seeds were floated in a liquid medium containing 5 percent sucrose, minerals and glutamine in flasks incubated at25 °C under 300 to 350 µE m2 s1 fluorescentlight. During 16 to 21 d in culture, seeds grew to a matured. wt of 100 to 600 mg per seed at an average rate of 5 to 25mg d. wt per seed d1 depending on initial size. Growthrates were maximal during the first 8 to 10 d in vitro but declinedwith loss of green colour in the cotyledons. Seed coats rupturedwith rapid cotyledon expansion during the first 2 d in culture.Embryos were tolerant to desiccation and 80 to 90 per cent germinatedif removed from culture before complete loss of green colour.The growth of excised seeds in vitro exceeded the growth ofseeds in detached pods, but when windows were cut in pods topermit direct exposure of seeds to the medium, seed growth wascomparable. Glycine max (L.) Merrill, soya bean, seed culture, seed growth, seed maturation, germination 相似文献
19.
Sweet pepper seeds were osmotically conditioned in 0.4 M mannitolsolution for 4 d (at 25 °C, in darkness) before or afterstorage at 35 °C for up to six months, and their germinationand viability was compared with that of untreated seeds storedunder the same conditions. Seeds that had been osmoconditionedprior to storage retained a high rate of germination and germinatedto a high final percentage (from 80 to 50 per cent) at both15 and 25 °C throughout the storage period. By contrast,both the rate and total level of germination of untreated pepperseeds declined rapidly at both germination temperatures, andby three months of storage the total level of seed viabilitywas already less than 10 per cent. Seeds that were first storedat 35 °C, and then osmoconditioned just prior to germination,showed a decline in germinability which when tested at 25 °Cwas the same as for untreated seeds, while tested at 15 °Coccurred at a slightly slower rate than for untreated seeds. It is evident that osmoconditioning prior to storage, in additionto the acceleration of germination, resulted in a dramatic delayof the ageing rate, thus increasing considerably the longevityof seeds. On the other hand, osmoconditioning after storagedid not seem to have any significant effect on seed viability,though it enhanced the germination rate. Capsicum annuum, sweet pepper, seed, germination, osmoconditioning, priming, storage, viability, ageing, longevity 相似文献
20.
Over 50 per cent germination has been obtained from Elaeis guineensisform pisifera seeds stored in unaerated sterile distilled waterfor 6 months. The moisture levels of the seeds and excised embryoswere of the same order (2030 and 6070 per cent,respectively) as those of fully imbibed fresh seeds. The implicationsof an apparent lower oxygen requirement by seeds stored underwater as against germinating seeds are discussed in the contextof the successful storage. Elaeis guineensis, pisifera, germination, seed dormancy, embryo 相似文献