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1.
THANOS C. A.; GEORGHIOU K.; DOUMA DIMITRA J.; MARANGAKI CHRISTIE J. 《Annals of botany》1991,68(5):469-475
Photoinhibition of seed germination was shown for Allium staticiforme,Brassica tournefortii, Cakile maritima and Otanthus maritimus,all plant species inhabiting sandy coasts of the MediterraneanSea. Germination of A. staticiforme was found to be typicallyMediterranean in regard to its temperature range (>020°C), while B. tournefortii germinated optimally at intermediatetemperatures (1525 °C). Light sensitivity was morepronounced in the latter species and 50 % inhibition of seedgermination was obtained with photon flux densities of approximately0.1 and 0.015 mol m2 d1 in A. staticiforme andB. tournefortii, respectively. However, the slopes of the regressionlines of germination plotted against the logarithm of whitelight flux density are similar in both species. From monthlyexperiments performed under fluctuating conditions of temperatureand light, simulating the elimate of Athens throughout the year,optimal germination response peaked in winterconditions for A. staticiforme, while a bimodal pattern wasobserved for B. tournefortii (maxima at the warm ends of therainy season). In contrast to the other plants, a fifth speciestested, Crithmum maritimum, showed an absolute light requirement,probably related to the rocky habitats of the species; the optimumgermination period coincided with the rainy season. Pot experimentswith seeds of the five species buried at various depths confirmedthat maximum emergence is favoured by shallow depths (0.51cm). It is concluded that seed germination in maritime plantsof the Mediterranean rim is mediated by a photoinhibition mechanismwhich can be considered an adaptation strategy against surfaceseedling establishment at the harsh, sandy or shingle, sea coasthabitats. Allium staticiforme, Brassica tournefortii, Cakile maritima, sea rocket, Crithmum maritimum, rock samphire, Otanthus maritimus, ton-weed, seed germination, light, photoinhibition, phytochrome, seedling emergence 相似文献
2.
Studies have been made on the time to germination and earlyseedling growth of the tomato Lycopersicon esculentum var. Potentateand Lycopersicon pimpinellifolium var. Red Currant, as wellas on derivative generations from their hybridization. Althoughtime to germination showed a genetic component, the relationshipsbetween different genotypes was much influenced by environmentalfactors. A marked maternal effect on time to germination dueto the varying seed sizes was noted while variation betweendifferent genotypes of similar seeds size was ascribed to anendospermic effect. The F1 hybrid embryo with L. Pimpinellifoliumas maternal parent contained more cells than that of the parentbut the hybrid cmbryo with L. esculentum as maternal parentcontained a similar number of cells to that of the parent itself.It is suggested that the results for embryo size both supportAshbys assertion that embryo size may be important indetermining heterosis, and also Hatchers findings in1940, that heterosis for hypocotyl extension is found in hybridsfrom parcnts of different sized seeds provided the small seededvariety is the maternal parent. 相似文献
3.
Naturally occurring gibberellin-like substances possessing acidic,basic, and neutral properties were detected, by paper partitionchromatography, in ethanolic extracts of tomato seed and ofetiolated seedlings after 72 and 116 hours' growth. Dwarf maizemutants of the d-1 and d-5 types, Meteor pea seedlingsand young Potentate tomato plants were used asbioassay material. Hydrolysis of seed and seedling proteinsby ficin in phosphate buffer, pH 6.2, after removal of ethanol-solublesubstances, liberated more and different boundgibberellin-like substances. It is suggested that protein hydrolysisduring germination is an important means of liberating thesesubstances at different stages of seedling development. Acidic substances were present in all the extracts prepared,but in general two with Rfs 0.25 and 0.55 in iso-propanol: ammonia:water : : 10:1:1 v/v were differentiated on d-2 and d-5 maizerespectively. Neutral substances in dry seed extracts chromatographedin the same solvent, had Rfs of 0.05, 0.35, and 0.95 and thesewere found only in the ethanolic (free) extracts.They were active on d-1 and d-2 maize and Meteorpea. Basic gibberellin-like substances with Rfs of 0.05 and0.35 were found in free extracts of both dry seedand etiolated seedlings after 116 hours' growth which were activeon d-2 maize only. Two others with Rfs 0.45 and 0.95 were extractedfrom seedlings after 72 hours' growth and these were activeon young Potentate tomato plants. It is suggested that certain gibberellin-like substances, capableof reversing dwarfism in test plants, may be responsible formorphogenetic or other responses not involving stem extensionin the parent species. Changes were found in the levels of gibberellin-likesubstances but there was no evidence of changes in levels ofseed inhibitors relative to seed growth substances. 相似文献
4.
Young plants of two selection lines of Lolium perenne cv. S23with fast and slow rates of maturetissue respiration were individually grown from seed,together with plants of S23, their common parent, in 9.2 cmpots in a controlled environment at 20/15 °C day/night temperatures. No significant differences were found between the genotypesin leaf extension and tiller production during this early stageof their growth. They did differ however, by an average of 26%,in the rate of dark respiration of fully expanded leaf laminae.The use of a simple model demonstrated that such a differencein respiration could alone account for the different rates ofdry matter production shown by the selection lines when grownas young crops from seed. Possible penalties of slowrespiration are also considered. Lolium perenne L., ryegrass, respiration, maintenance respiration, stimulated swards, leaf growth, tiller production, carbon economy 相似文献
5.
The effect of the leafless mutation (in whichtendrils replace leaflets and the stipules are reduced to avestigial form) upon foliage area, photosynthetic net CO2 uptakepotential, dry matter production and seed yield in Pisum sativumwas studied by comparing two near-isogenic lines of genotypeafafstst and ++++. The mutation is of potential agronomic valuein that it offers improved lodging resistance, crop drying andharvester throughput. In the conventional phenotype the total foliage area of themain axis attained a plateau (456 cm2) at day 56 from seedlingemergence, whereas corresponding values for the leaflessmutant showed a total area of 208 cm2 at day 68 with no indicationof a plateau. The agronomic consequence of this is discussed.During the vegetative phase of the plant the maximum CO2 uptakepotential in the fully expanded conventional leaf was 8·5mg CO2 leaf1 h1 and in the leaflessmutant this value was 7·0 mg CO2 leaf1 h1.For most leaves of the latter phenotype this valuewas between 30 and 60 per cent less than for their conventionalcounterpart. There was a consistently higher photosyntheticpotential per unit area in tendrils of the leaflessmutant than in leaflets of the conventional phenotype. The respectivemean specific values for the two phenotypes were 53 and 37 mgCO2 dm2 h1. The problem of obtaining a meaningfulsurface area value for tendrils is discussed and the cylindricalnature of tendrils is taken into account. The leafless mutant consistently accumulated 50per cent less dry matter than did conventional plants in theperiod from seedling emergence to anthesis and yield of maturedry seed per plant showed a reduction of 50 per cent both inseed number and total seed weight. The implications for future breeding and selection programmesaimed at haulm reduction are discussed in relation to evaluatingthe ability of the background genotype to produce adequate tendrilsin the presence of afafstst. Triticum aestivum, wheat, callus culture, organogenesis 相似文献
6.
The response of the germination of seeds of Barbarea vema (Mill.)Aschers, Brassica chinensis L., Brassica juncea (L.) Czern.& Coss., Brassica oleracea L. var. gongylodes L., Camelinasaliva (L.) Crantz, Eruca saliva Mill., Lepidium sativum L.,Nasturtium officinale R. Br., and Rorippa palustris (L.) Besserto white fluorescent light of different photon flux densitiesapplied for different daily durations in a diurnal alternatingtemperature regime of 20 °C/30 °C (16 h/8 h) was quantifiedby linear relations between probit percentage germination andthe logarithm of photon dose, the product of photon flux densityand duration. The low energy reaction, in which increasing dosepromotes germination, was detected in all the seed populationsbut in Barbarea vema and Brassica Juncea the lowest photon doseapplied (1052 and 105 7 mol m2 d1,respectively) was sufficient to saturate the response. Comparisons,where possible, between photoperiods demonstrated reciprocity,i.e. germination was proportional to photon dose irrespectiveof photoperiod, for the low energy reaction in Brassica oleracea(1 min d1 to 1 h d1), Camelina saliva (1 min d1to 8 h d1), Eruca saliva (1 min d1 to 24 h d1),Lepidium sativum (I min d1 to 8 h d1) and Rorippapalustris (1 min d1 to 8 h d1), but not in Brassicachinensis and Nasturtium officinale. The high irradiance reaction,in which increasing dose inhibits germination, was detectedin Barbarea vema, Brassica chinensis, Brassica juncea, Brassicaoleracea, and Camelina saliva. The minimum dose at which inhibitionwas detected was lO03 mol m2 d1.These results are discussed in the context of devising optimallight regimes for laboratory tests intended to maximize germination The response of germination to photon dose was also quantifiedwith 3 x 104 M GA2, co-applied (Brassica chinensis, Camelinasaliva, and Lepidium sativum) and with 2 x 102 M potassiumnitrate co-applied (Brassica chinensis). In the latter casepotassium nitrate had no effect in the dark and inhibited germinationin the light, but GA2, promoted germination substantially inall three species. Variation amongst seeds in the minimum photondose required to stimulate germination was not affected by co-applicationof GA2, in Brassica chinensis and Camelina saliva, whereas seedsof Lepidium salivum showed a narrower distribution of sensitivitiesto the low energy reaction in the presence of GA2 Barbarea vema (Mill.) Aschers, Brassica chinensis L., Brassica juncea (L.) Czern. & Coss., Brassica oleracea L. var. gongylodes L., Camelina saliva (L.) Crantz, Eruca saliva Mill., Lepidium satiaum L., Nasturtium officinale R. Br., Rorippa palustris (L.) Besser, Cruciferae, light, gibberellic acid, seed germination, seed dormancy 相似文献
7.
The Growth and Carbon Allocation Patterns of White Clover (Trifolium repens L.) Plants of Contrasting Branching Structure 总被引:1,自引:0,他引:1
The growth, morphology and carbon allocation patterns of F1progeny white clover (Trifolium repens L.) plants selected foreither low (LBF) or high (HBF) frequencyof stolon branching were compared in two controlled-environmentexperiments. Selections from within both a small-leaved (GrasslandsTahora) and a large-leaved (Grasslands Kopu)clover cultivar were compared, and plants were grown under arelatively lenient defoliation treatment (expt 1) or under threelevels of defoliation seventy (expt 2). Carbon allocation patternswere measured by 14CO2 pulse-chase labelling using fully unfoldedleaves on the main (parent) stolon. LBF and HBF displayed consistent differences in the selectedcharacter though, within cultivars, the difference between selectionswas most pronounced for Kopu. The selections developed fundamentallydifferent branching structures resulting from differences inbranching frequency, with total branch weight per plant averaging122 mg for LBF and 399 mg for HBF (mean of both experiments).More C moved from parent stolon leaves to branches in HBF thanin LBF (mean 22.6% vs. 15.1% respectively of the 14C exportedfrom source leaves). More C also moved to stolon tissue in HBF,but, counterbalancing this and the difference in allocationto branches, less moved to developing leaves and roots on theparent stolon itself compared to LBF. However, the total weightof developing leaves and roots per parent stolon was generallygreater in HBF than in LBF, probably reflecting greater C importby these sinks from the higher number of branches present perplant in the former selection. HBF plants were consistentlylarger at harvest than LBF plants. There were no defoliationtreatment x selection interactions in C allocation patternsin expt 2. The implications of the results for plant performancein grazed pastures are discussed. Branching, carbon translocation, defoliation, growth, morphology, Trifolium repens, white clover 相似文献
8.
The Sensitivity of Net Photosynthesis in Several Plant Species to Short-term Fumigation with Sulphur Dioxide 总被引:4,自引:0,他引:4
The effects of exposure of up to 2 h with sulphur dioxide ona range of plant species was observed by measuring changes inthe rate of net photosynthesis under closely controlled environmentalconditions. Ryegrass, Lolium perenne S23 was thespecies most sensitive to SO2; significant inhibition was detectedat 200 nl l1. Fumigations at 300 nl l1 also inhibitedphotosynthesis in field bean (Vicia faba cv. Three FoldWhite and Blaze) and in barley (Hordeumvulgare cv. Sonja). No effect was detected inwheat (Triticum aestivum cv. Virtue) at concentrationsup to 600 nl l1 SO2, or in oil-seed rape (Brassica napuscv. Rafal) except at 800 nl l1 SO2). Recoverycommenced immediately after the fumigation was terminated andwas complete within 2 h when inhibition had not exceeded 20%during the SO2 treatment. Key words: Sulphur dioxide, short-term fumigation, photosynthesis 相似文献
9.
Flowering of Raphanus sativus L. (Japanese radish, cultivarWase-shijunichi) is hastened by vernalizationbut non-vernalized radish could flower under continuous illumination.Days from germination to anthesis in non-vernalized plants fluctuateddepending on the period of seed storage, and this fluctuationshowed an annual rhythm. On the contrary, the days to anthesisin vernalized radish remained nearly constant for 2 years.
1Present address: Department of Horticulture. Gangweon NationalUniversity, Chuncheon 200, Korea. (Received November 25, 1975; ) 相似文献
10.
Dry legumes of Sesbania punicea (Cav.) Benth. contain impermeableseeds which are either beige-greenish or reddish. When keptin water for over one year they do not swell. Quick imbibitionwas induced by a deep cut, abrasion with coarse abrasive paper,immersion in concentrated sulphuric acid, in boiling water andin boiling KOH solutions. Neither lipid solvents (acetone, chloroform,cyclohexane, diethyl ether, ethanol, xylene), nor, at room temperature,KOH solutions up to 50% per cent, permeabilized the seeds. Astrong barrier to water entry appeared to be located in thepalisade layer which showed light points in places,and which seemed to be transversal thickenings. In the testa, callose, which may play a role in the impermeabilityof the Sesbania punicea seed, was detected. Sesbania punicea, germination, seed dormancy, seed coat impermeability, callose 相似文献
11.
Imbibition of seeds of oil seed rape (Brassica napus cv Jetneuf)in 103 M aminoethoxyvinylglycine (AVG) or 102silver thiosulphate (Ag+) had no effect on germination nor onthe emergence of seedlings from uncompacted or lightly compressedsoil, but significantly reduced emergence from moderately compressedsoil of 68.4 or 143.3 N cm2 impedance. Exertion of force by emerging control seedlings against a staticcantilever bar fitted with strain gauges reached a maximum (Fmax)of 6 g over 10 h. Higher axial forces were achieved when theseedlings were emerging from compressed soil, without any changein the time required to reach Fmax, so that the build-up offorce was considerably (1.8 fold) faster than in uncompressedsoil. This adaptive response to soil impedance was modified by theseed pretreatments employed. Seedlings from AVG or Ag+pretreatedseeds produced lower axial forces than controls, and neitherFmax nor the rate at which force developed showed any responseto soil compression. After pretreatment in 103 ethephon or 104 naphthaleneacetic acid (NAA) the seedlings achieved similar Fmax to controlseedlings, but responded more rapidly to soil compression sothat the rate of build up of emergence force was 2.3 fold (NAA)or 2.8 fold (ethephon) faster in compressed than in uncompressedsoil. The results suggest that the exertion of force by a seedlingagainst a barrier involves a dynamic response to impedance onthe part of the seedling. This response can be either enhancedor suppressed by substances which affect ethylene productionor ethylene action. Such compounds may have promise for modifyingseedling emergence from impeding soils. Brassica napus, oil seed rape, seedling emergence, soil compaction, ethylene, Ethrel, silver, aminoethoxyvinylglycine, naphthalene acetic acid 相似文献
12.
Seed conditioning and germination in witchweed (Striga asiatica(L.) Kuntze) were temperature-dependent. With higher conditioningtemperatures, shorter conditioning time was required for germinationwith terminal dl-strigol (strigol) treatment at 30 °C. Maximumgermination (80100%) was obtained by conditioning inwater at 20, 25, 30 and 35 °C for 14, 7, 5 and 3 d, respectively,and terminally treating with 106 M strigol at 30 °C.Seeds conditioned in 108 M strigol instead of water germinatedmuch less with the same terminal strigol treatment. Generally,conditioning was slower when seeds were conditioned in strigolrather than water. The reduction in germination rate by pretreatmentin strigol or pretreatment at low temperatures could be overcomeby increasing the terminal strigol concentration in the germinationtest. Conditioned seeds did not germinate at 10 and 15 °Cwith a terminal 106 M strigol treatment but yielded closeto maximum germination at 25, 30 and 35 °C with the sameterminal strigol treatment. To obtain maximum germination, boththe minimum conditioning temperature and the minimum germinationtemperature for conditioned seeds were 20 °C. Factors suchas conditioning time, and strigol concentration and temperatureduring conditioning and/or germination determine whether seedsremain in the conditioning phase or shift to a germination phase. dl-Strigol, germination stimulation, parasitic plants, seed conditioning, seed germination, Striga asiatica, temperature, weed control 相似文献
13.
After removal of the embryo from developing seeds of Pisum sativum,the empty ovules (seed coats without enclosedembryo) were filled with a solution (pH 5.5) containing mannitol(usually 400 mM) to which various salts were added. A solutioncontaining two isotopes ((a) [2H]-sucrose/[14C]aminoisobutyricacid (AIB) or (b) [3H]valine/[14C]asparagine mixture) was administeredto the plant via the petiole subtending the fruiting node, and[2H]solute and [14C]solute unloading from the seed coat wasmeasured, in pulse-labelling experiments of about 5 h. The presenceof 25 or 50 mM K+ in the empty ovule enhancedthe release of sucrose from the seed coat particularly duringthe first hours of the experiment, but the stimulating effectof K+ on the release of labelled solutes derived from aminoacids was much smaller. The presence of 25 mM CaCl2 did notaffect the release of sucrose or amino acids from the seed coat.The effect of K+ on sucrose and amino acid release is explainedas an inhibition of sucrose and amino acid resorption from theseed coat apoplast into seed coat cells, after unloading fromthe seed coat unloading sites. It is suggested that amino acidrelease is much less affected by K+ than sucrose release, becausefar less resorption of amino acids by seed coat parenchyma cellstakes place during amino acid transport into the seed coat cavity. Pisum sativum, pea, assimilate transport, assimilate unloading, seed-coat exudate, seed development, sucrose resorption, surgical treatment 相似文献
14.
The Importance of Light Intensity for Pollen Tube Growth and Embryo Survival in Wheat x Maize Crosses 总被引:1,自引:0,他引:1
The success of Triticum aestivumxZea mays crosses, used to producewheat doubled haploids, is influenced by light intensity. Toexamine the basis for this response, pollen tube growth, embryosurvival and indicators of photosynthetic rate were measuredin two wheat cultivars (Karamu and Kotuku)crossed with maize at two irradiance levels (250 or 750 µmolm-2s-1, PAR). Pollen tube growth was significantly affectedby light intensity in Karamu plants but not inKotuku plants, despite both cultivars being pollinatedby the same maize source. The percentage of pollen tubes reachingthe cavity between the ovarian wall and integuments, or in themicropyle of Karamu plants at high light intensity(65%) was nearly three-times greater than that at low lightintensity (22%). Thus, either low light intensity can affectthe maternal wheat plant in a way that inhibits pollen tubegrowth and/or high light intensity may promote pollen tube growthin Karamu plants. Significant differences in ratesof electron transport in plants grown at the two light intensitiesindicated that the rate of photosynthesis may also have an effecton pollen tube growth. These results have importance for improvingthe efficiency of wheat x maize crosses and other wide cerealcrosses. Copyright 2001 Annals of Botany Company Intergeneric hybridization, light intensity, pollen tube growth, embryo survival, Triticum aestivum, wheat,Zea mays , maize 相似文献
15.
Haploid Culture and UV Mutagenesis in Rapid-cycling Brassica napus for the Generation of Resistance to Chlorsulfuron and Alternaria brassicicola 总被引:5,自引:0,他引:5
The effect of ultra violet (UV) irradiation on cultured isolatedmicrospores of rapid cycling Brassica napus was investigated.The microscpores were highly sensitive to UV, with the calculatedLD50 being an exposure of 20 s. Viability tests suggested thatdeath of the microspores was not immediate, but occurred duringsubsequent incubation (7 d). None of the embryos produced followingUV-irradiation of microscpores showed gross morphological variation.A large number of regenerants was established from embryoidsand grown to flowering. These plants set fertile seed afterselfing. The progenies were assessed for resistance to Alternariabrassicicola and a small number showed increased resistanceto the pathogen, suggesting the generation of novel heritableresistance to this pathogen. In vitro selection revealed heritableresistance to the herbicide Glean (active ingredientchlorsulfuron). Brassica napus, microspore culture, UV light, mutagenesis, selection, disease resistance, herbicide, Alternaria brassicicola 相似文献
16.
Effect of Cultivar, Temperature and Seed Size on the Germination and Emergence of Soya Beans (Glycine max (L.) Merr.) 总被引:2,自引:0,他引:2
The rapid and uniform establishment of soya bean [Glycine max(L.) Merr.] stands is conducive to higher yields. This studywas undertaken to determine the effects of cultivar, temperature,and seed size on the rate of germination and emergence. No cultivar effect on the germination rate was observed. However,in an emergence study from a sand-soil-peat mixture, cultivardifferences in emergence rates were noted(Chippewa 64> Wayne > Amsoy 71). In anotheremergence study (sand media) the cvs Calland andWilliams emerged faster than the cv. 'Wayne orWells. Time required for 50 per cent germination decreased (18.84.0days) as the temperature increased from 10 to 30 °C (5 °Cincrements). Emergence (50 per cent) from a sand-soil-peat mixturewas more rapid (19.86.3 days) as the simulated plantingdate (growth chamber set to simulate field temperatures) wasdelayed from 16 April to 15 June with an intermediate date of16 May. In addition, time required for 50 per cent emergence of thecultivars from sand decreased (79376 h) as the temperaturewas increased from 10 to 30 °C with no decrease from 30to 35 °C. Seed size effects were apparent, with the very small seed germinatingslower than the three larger seed sizes. In the emergence studieswith both the sand and sand-soil-peat mixture there was a generaltrend toward more rapid emergence with the smaller seeds. However,the absolute differences were small. Significant cultivar x temperature interactions were observedfor the germination and emergence rates. In most cases the cultivarsmerged in terms of germination and emergence rates at temperaturesbetween 10 and 20 °C and at the higher temperatures thecultivar rankings were different from those observed at temperaturesbelow the merging point. Glycine max (L.) Merr, soya bean, seed germination, establishment of seedlings 相似文献
17.
Development of seeds following pollination with irradiated pollenwas studied inActinidia deliciosa(kiwifruit) Hayward.Pollinations were carried out using two different sources ofpollen (Tomuri and Matua) irradiatedwith gamma rays at doses of 700 and 900 Gy. Non-irradiated crosseswere used as controls. Pollen irradiation had little effectonin vitropollen germination. Irradiated pollen affected seedset and seed content, and induced the formation of parthenogeneticembryos. In comparison to the control, the embryo growth ratewas slower and the endosperm contained very low amounts of storageproducts. Seed set was significantly reduced following bothdoses of irradiation. Two types of seeds were observed: (1)seeds with endosperm only; and (2) seeds with both embryo andendosperm. The proportion of seeds containing endosperm onlywas almost ten-fold higher than those containing both embryoand endosperm. Embryo production by gamma-irradiated pollenwas genotype- and dose-dependent. The induction of parthenogenesiswas higher following gamma ray doses of 900 Gy than 700 Gy,which suggests the Hertwig Effect; the best efficiencywas obtained with Tomuri pollen. Ploidy levelof parthenogenetic embryos was evaluated by nuclear size (area)with the use of image analysis. There was a large differencein embryo nuclei size between control and parthenogenetic embryos(mean size 90.8 and 49.1 µm2, respectively). It is concludedthat parthenogenetic embryos represent trihaploids.Copyright1998 Annals of Botany Company. Actinidia deliciosa, kiwifruit, pollen irradiation, induced parthenogenesis. 相似文献
18.
The activity of sodium hypochlorite solution in relieving thermo-inhibitionof germination of lettuce seed is shown to be due to its chlorinecontent. Results of experiments in which the pericarp, and pericarpand endosperm were removed, together with direct measurementsof penetration forces, suggest that the relief of thermo-inhibitionresults from weakening of the pericarp by the hypochlorite.Differences between the cultivars Cobham Greenand Grand Rapids in the contributions made bypericarp and endosperm to germination control at 35 °C aredemonstrated. Key words: Lactuca sativa L, Chlorine, Thermo-inhibition 相似文献
19.
The prediction that very high seed yields of dry beans (Phaseolusvulgaris L.) would be produced by the delayed transplantingof large plants has been tested in a factorial experiment withfour dates of transplanting and eight plant populations. Therewere significant differences in yield between transplantingdates and between population densities, and there was a significantdate-density interaction. At low plant densities (up to about30 plants m2) the three transplanted treatments yieldedless than the hand-sown controls, and late transplanting yieldedless than early. At the highest density the situation was reversed;all three transplanted treatments out-yielded the controls andlate transplanting tended to out-yield plants transplanted early.The biggest yield was 340 g seed m2 from a transplantedcrop grown at 35 plants m2. The data on yield fitted a modified rectangular hyperbola ofthe form where y is yield per unit area, p is the number of plants perunit area, t is the number of days between sowing and transplanting,and Bo, n, m, and p are arbitrary parameters. This equationaccounted for 91 per cent of the variation in yield with t andp. It is suggested that late transplanting had adverse effects,due to transplanting shock and which were mostmarked at low plant densities; and beneficial effects, ascribableto an effect on plant plasticity, which were mostmarked at high plant densities. Possible physiological mechanismsof these effects are discussed. Phaseolus vulgaris, yield, density, transplanting 相似文献
20.
SINGH N; SINGH S N; SRIVASTAVA K; YUNUS M; AHMAD K. J; SHARMA S C.; SHARGA A N 《Annals of botany》1990,65(1):41-44
Five Gladiolus cultivars, namely Aldebaran, BrightEye, Illusion, Manisha andManmohan, were exposed to 1 and 2 µg l1sulphur dioxide to test their relative-sensitivity toleranceto the pollutant Plants were fumigated experimentally for 2h daily Foliar injury symptoms were observed first in Manishafollowed by Aldebaran and Illusionat the higher dose Photosynthetic pigments and leaf extractpH were significantly decreased, particularly in Manishaand Illusion Overall disturbances in the plantmetabolism due to SO2 treatment led to retarded growth of plants,as evident from decreased shoot length and phytomass valuesThe order of sensitivity of the five Gladiolus cultivars toSO2 was as follows, with the greatest first Manisha, Illusion,Aldebaran, Bright Eye, Manmohan Cultivars, Gladiolus, sensitivity, sulphur dioxide, tolerance 相似文献