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1.
Three lines of evidence correlate the parasitic performane ofOrthocarpus purpuruscens Benth. with numbers of haustoria produced:(i) the pattern of variation in numbers of haustoria producedin agar culture with different chemical stimuli correspondsclosely to the variation pattern of parasite vigour producedby a range of host plants; (ii) the progeny of plants demonstratingvigorous growth with hosts produce significantly more haustoriathan progeny from parents exhibiting weak parasitic development;(iii) conversely, seedlings that produce high numbers of haustoriain agar culture grow significantly better when transplantedwith hosts than do seedlings with low numbers of haustoria.Haustoria-forming potential is heritable, but highly influencedby environmental factors. Potential number of haustoria is aproduct of the concentration and/or quality of haustoria inducingstimuli, and the parasite's individual ability to respond. Intra-populationdifferences in parasitic development appear to be largely dueto the quantity rather than the quality of substrates receivedfrom host plants. haustoria, Orthocarpus purpurarcens, parasitic development 相似文献
2.
Excised sorghum root segments (510 mm in length) werecultured for 50 d in four different liquid media containingmineral salts, vitamins, amino acids, glucose, and IAA. Theroots were removed and the remaining medium was solidified withan equal volume of warm 16% water agar. Dry unconditionedor conditioned Striga asiatica seeds were transferred to themedium. Some of the seeds germinated and developed into parasitic-typeseedlings. These seedlings had haustoria, tubercles, dense roothairs, branched shoots, and multiple shoot-borne adventitiousroots. The plumule pole developed into a shoot, but the radiclepole displayed only rudimentary development. On the same media,but which had not previously been used to grow sorghum roots,the seedlings displayed a well-developed radicle-derived rootsystem, but the plumule did not grow. Shoots began to appearon the roots only after 3550 d of culture. These seedlingshad no haustoria, no tubercles, few or scattered root hairs,no shoot-borne adventitious roots and few shoot branches, andappeared to be non-parasitic-type seedlings. Shoots grew ina medium supplemented with IAA and kinetin, but did not in amedium containing NAA plus IBA. On replacement of glucose andIAA with sucrose and 2,4-D, respectively, Striga seeds germinated,and the heart-shaped embryos dedifferentiated into calli. Thecalli have been maintained by subculturing for over 9 months.The results demonstrated that a host signal, in addition tothose for germination and haustorium formation, is requiredfor further development. Moreover, morphogenesis of culturedS. asiatica is influenced by exogenous growth regulators. Key words: Striga asiatica, parasitic weeds, haustoria, Sorghum bicolor, in vitro culture 相似文献
3.
We recently described an in vitro approach that uses root culturesto study haustorial formation in Striga asiatica. Previous studieshave used haustoria formed on intact radicles of Striga seedlings.In vitro cultured roots formed haustoria that appeared morphologicallysimilar to those formed by Striga radicles, but were 510-foldlarger. In this study, we provide biochemical and histologicalevidence to support further the similarity of root culture haustoriato haustoria formed on radicles of seedlings. We examined invivo protein synthesis during haustorial development on rootcultures and radicles by 2-D PAGE. Four proteins increased inabundance in both root cultures and radicles after 6 h of haustorialinduction. All four proteins appeared transiently in root culturesand radicles, being more abundant at 6 h, and less abundantafter 24 h of haustorial induction. Only three of the four haustorial-specificproteins were more abundant in root cultures after 2 h of haustorialinduction; all four had decreased in abundance after 12 h ofhaustorial induction. Using light microscopic analysis we comparedthe ontogeny of root culture haustoria to that of haustoriaon radicles. These studies revealed that root culture haustoriaundergo developmental changes similar to those reported forradicle haustoria such as early expansion of cortical cells,the emergence of haustorial hairs from epidermal cells, andthe development of densely staining cells at the haustorialapex. In addition, these changes occurred within a similar time-frameand sequence in root culture and radicle haustoria. Finally,root culture haustoria were found to be capable of attachingto sorghum host roots. Key words: Striga asiatica L., Kuntze, haustoria, root cultures, proteins, histology, 2D-PAGE 相似文献
4.
Dry matter gains and haustorial production of pot-cultured seedlingsof Nuytsia floribunda were assessed after a 12 month periodof association singly with each of a range of potential woodyhost species. One species,Adenanthos cygnorum , of similar sizeto most parasitized hosts, served as measure of response ofNuytsia in a non-benefiting situation. Rated on this basis,all 23 parasitized hosts elicited greater mean dry weights ofNuytsia than when on Adenanthos, and seven of these instanceswere highly significant. Numbers and weights of penetratingand presumably functional haustoria formed on a host were broadlycorrelated with growth benefit to Nuytsia, but there were notableinstances of unusually poor or great benefit from a host relativeto the complement of haustoria involved. Experiments in whichhaustoria-bearing associations of Nuytsia partnered with nodulatedAcacia hosts (Acacia acuminata and A. cyclops) were fed15N2showedsignificant transfer of15N to the parasite, but failed to determinewhether the label had been acquired through haustoria or directlyby Nuytsia roots following turnover of nodule and root residuesof the host in the rooting medium. A parallel study using theunusual non-protein amino acid, djenkolic acid, as a markerof benefit from the djenkolic acid-containing host A. cyclops,showed appearance and progressive build-up of the compound infoliage of Nuytsia over a 6 month period after partnering thespecies in pot culture. Presence of the compound at final harvestin xylem sap of both partners but not in soil solution of thecultures strongly indicated xylem transfer via haustoria asthe principal avenue for N benefit to the parasite. Resultsare discussed in relation to a recent evaluation of haustorialstructure and functioning of N. floribunda. Copyright 2000 Annalsof Botany Company Root hemiparasite, Nuytsia, Loranthaceae, growth benefit, haustorial production, nitrogen transfer from hosts 相似文献
5.
Solute composition of root xylem sap of common native hostsof quandong (Santalum acuminatum) was compared with that ofcorresponding xylem sap and ethanolic extracts of endophytictissues of haustoria of the hemiparasite. Each host transporteda characteristic set of organic nitrogenous solutes, but littleor no nitrate, and the data indicated only limited direct flowof amino compounds between xylem streams of hosts and parasite.Proline predominated in the haustorium and xylem ofSantalum,but was at negligible levels in the xylem of most hosts. Sucrose,fructose, glucose, malate and citrate were at high levels inall saps, and fructose especially prominent inSantalum. Chloride,sulphate and phosphate were the principal inorganic anions ofthe xylem. Based on C:N ratios of xylem and dry matter ofSantalumandassuming a 70% or more dependence on the host for N, it wasestimated thatSantalumwould gain approximately one third ofits C requirement for dry matter production heterotrophicallyfrom the xylem of its hosts. Infiltration of xylem of haustoria-bearingroot segments of a major host (Acacia rostellifera) with a rangeof15N labelled substrates resulted in 4080% of the15Nof endophytes of the attached haustoria being received as proline.Nitrate reductase activity was induced in haustoria followinghost xylem feeding of nitrate. The study concludes that haustoriaofSantalumact as a major site of synthesis and export of prolineand might therefore play an important role in osmotic adjustmentof the parasite and its related acquisition of water from hosts. Root hemiparasite; Santalum acuminatum; 15N labelled substrates; xylem transport; proline; osmoregulation 相似文献
6.
《Phytochemistry》1986,25(10):2291-2298
Host recognition by the angiosperm root parasite Agalinis purpurea occurs through the development of haustoria, organs specialized for the attachment and penetration of host roots. Axenic cultures of Agalinis do not develop haustoria, but low molecular weight compounds produced by host plants induce haustoria development. Structure-activity studies have shown that highest levels of haustoria induction are afforded by flavonoids bearing specifically substituted methoxyphenol functionality. This paper examines Lespedeza sericea to determine the extent of this structure-activity relationship among hosts of Agalinis. A pentacyclic triterpene has been isolated from Lespedeza roots as a haustoria inducer, and extensive NMR and mass spectral experiments led to its characterization as soyasapogenol B (3β,22β,24-trihydroxy-olean-12-ene). The activity of soyasapogenol B is lower than the phenolic inducers, and modification of hydroxyl substitutents on soyasapogenol B abolishes activity. This haustoria inducer appears to be preferentially secreted from the roots of Lespedeza, but not in quantities sufficient to account for all haustoria inducing activity exhibited by the crude root exudate. 相似文献
7.
Esashi Yohji; Kusuyama Kazutoshi; Tazaki Seiryoh; Ishihara Nobuyori 《Plant & cell physiology》1981,22(1):65-71
When applied singly, KCN or NaN3, as inhibitors of the cytochromerespiration path, and benzohydroxamic acid or n-propyl gallate,as inhibitors of the alternative respiration path, were lesseffective and ineffective, respectively, in inducing germinationof secondarily dormant, upper seeds of Xanthium pennsylvanicumWallr. When applied in combination, however, these chemicalswere very effective, producing much higher gemination. Thus,we concluded that an appropriate balance between the cytochromeand alternative path fluxes is required to induce the germinationof secondarily dormant cocklebur seeds. (Received August 30, 1980; Accepted December 2, 1980) 相似文献
8.
Seeds of Scurrula pulverulenta, a leafy mistletoe, germinatedon a simple nutrient medium, and addition of casein hydrolysate(CH) supported better growth of the seedlings. In either casethe seedlings developed haustoria which were comparable to thehaustoria formed in vivo inside the host tissue. On White'smedium (WM)+CH+indole-3yl-acetic acid (IAA) the embryo callusedand, subsequently, differentiated shoot buds and/or haustoria.On WM+CH+IAA+ kinetin the callused embryo did not differentiatehaustoria or shoot buds. However, on this medium, embryoidsdeveloped up to the heart-shaped stage. The effects of somecytokinins, coconut milk, and water-melon juice, on germination,proliferation of embryo, and differentiation of shoot buds fromthe callus were also studied. 相似文献
9.
Growth, Resource Allocation and Haustorial Biology of the Root Hemiparasite Olax phyllanthi (Olacaceae) 总被引:1,自引:0,他引:1
Olax phyllanthi was found to parasitize a wide range of taxain the native habitat in coastal heath, South-West Australia.All major life and growth forms were regularly exploited, includingmost woody dicotyledons (except members of the Myrtaceae), afew monocotyledons and cohabiting root hemiparasites. Initiationof haustoria occurred mostly in autumn (southern hemisphere),with some senescing the following summer, and others survivinguntil replaced by a new generation of haustoria the followingautumn. Seedlings increased in dry matter and contents of N,P, K, Mg and Ca during preparasitic development, but did notsurvive beyond 6 months if failing to establish haustoria ona suitable host. Plant dry matter, mineral content and haustorialnumber increased exponentially during subsequent parasitic development.Mean shoot:root d. wt ratios of 1st to 3rd-year plants lay withinthe range 1.21.4. Root systems were laterally extensiveand restricted to the top 40 cm of rooting substrate. Mean totalroot lengths of 2nd- and 3rd-year plants were 7.1m (n = 5) and60.9 m (n = 5), respectively. Haustoria comprised 0.73.5%of plant d. wt, with a mean of 7.9 haustoria (n = 10, 2nd- and3rd-year plants) per metre of root length. Comparisons of mineralconcentrations in dry matter of O. phyllanthi and of a rangeof commonly parasitized hosts showed the parasite to be muchricher on average than its hosts in K, P, and to a lesser extentin N, but not noticeably different in Mg and Ca. Olax, root hemiparasite, mineral nutrition, haustoria, resource allocation 相似文献
10.
The effects of kinetin and the interaction between kinetin andsalinity on seed germination of three plant species namely Lycopersiconesculentum, Hordeum vulgare and Gossypium hirsutum were studiedKinetin was applied exogenously to the seeds in order to determinewhether this growth-promoting hormone would promote germinationand to see if osmotically-induced dormancy caused by NaCl couldbe alleviated The results indicate that kinetin is capable ofbreaking dormancy in these species and there is a significantinteraction with salinity in tomato and cotton Kinetin, germination, salinity, water stress, salt stress, Lycopersicon esculentum Mill, tomato, Hordeum vulgare L, barley, Gossypium hirsutum L, cotton 相似文献
11.
Tissue-invasive pollen tube branching occurs in an Australianshrub, Grevillea banksii R.Br. (Proteaceae). Parenchyma andphloem of the ovary wall are soon infiltrated after fertilization,by intercellular branches and the lumina of xylem elements areentered. Ovular tissues are not affected. Grevillea banksii, pollen, haustoria, ovary wall 相似文献
12.
When Phaseolus mungo seeds were allowed to germinate in 520mM quinate solution in the dark, a marked increase in the endogenousshikimic acid level occurred in their tissues. The acid levelrose distincdy on the 2nd day of germination and reached a maximumon the 4th day. The quinate-14C fed to germinating seeds waspredominantly converted to shikimic acid, and little radioactivitywas found in 3-dehydroshikimic acid. When quinate-14C was suppliedsimultaneously with relatively high concentrations of 3-dehydroquinicacid or 3-dehydroshikimic acid, its conversionto shikimic acidwas restrained, but hardly any radioactivity was trapped ineither of the dehydro compounds. 3-Dehydroquinic acid-14C or3-dehydroshikimic acid-14C fed to the seeds was metabolizedpreferentially to shikimic acid. The experimental results arediscussed with respect to the metabolic relationship betweenquinic acid and odier alicyclic acids in the aromatic biosynthesisof P. mungo seedlings. (Received October 16, 1975; ) 相似文献
13.
Assay of amino-peptidase, acid and alkaline phosphatase, esteraseand ß-glucosidase activity in the haustoria and suspensorof Tropaeolum majus embryos at different stages of developmentis made to evaluate the function of hydrolases in autolysisof the suspensor. Enzyme activities rise to a maximum sometimebetween heart-shaped and cotyledonary phases of embryo development. Tropaeolum majus L. nasturtium, embryology, suspensor, autolysis, hydrolytic enzymes 相似文献
14.
Shiota Hajime; Satoh Rika; Watabe Ken-ichi; Harada Hiroshi; Kamada Hiroshi 《Plant & cell physiology》1998,39(11):1184-1193
A carrot gene homologous to the ABI3 gene of Arabidopsis wasisolated from a carrot somatic embryo cDNA library and designatedC-ABI3. The sequence of C-ABI3 was very similar to those ofABI3 of Arabidopsis and VP1 of maize in certain conserved regions.The expression of C-ABI3 was detected specifically in embryogeniccells, somatic embryos and developing seeds. Thus, expressionof C-ABI3 was limited to tissues that acquired desiccation tolerancein response to endogenous or exogenous abscisic acid (ABA).Endogenous levels of ABA in seeds increased transiently andthen desiccation of seeds started. The expression of C-ABI3in developing seeds was observed prior to the increase in levelsof endogenous ABA that was followed by desiccation of seeds.In transgenic mature leaves in which C-ABI3 was ectopicallyexpressed, expression of ECP31, ECP63 and ECP40 was inducedby treatment with ABA, which indicates that the expression ofECP genes was controlled by the pathway(s) that involved C-ABI3and ABA. This suggests that C-ABI3 has the same function asVP1/ABI3 factor in carrot somatic embryos. (Received March 4, 1998; Accepted September 4, 1998) 相似文献
15.
Phytochrome Participation in Induction of Haustoria in Cuscuta japonica, a Holoparasitic Flowering Plant 总被引:1,自引:0,他引:1
Furuhashi Katsuhisa; Tada Yoshifumi; Okamoto Kazuhisa; Sugai Michizo; Kubota Mamoru; Watanabe Masakatsu 《Plant & cell physiology》1997,38(8):935-940
Seedlings of Cuscuta japonica pasted on an acrylic plate developedmany haustoria in response to far-red light after pre-irradiationwith white light. The effect of far-red light was cancelledcompletely by red light irradiated immediately after the far-redlight. In order to elucidate the photoreceptor(s) for photocontrolin the induction of haustoria, action spectra for the photo-inductionand its reversion were determined in the wavelength region from340 nm to 800 nm using the Okazaki Large Spectrograph. The action spectrum for the induction of haustoria had a pronouncedpeak at 740 nm and a small peak at 420 nm, while the actionspectrum for reversal of the induction had a pronounced peakat 660 nm and a small peak at 380 nm. These results indicatethat phytochrome is involved in the photocontrol of inductionof haustoria in Cuscuta japonica. Considering the far-red /redreversibility, it was suggested that phytochrome B is the photorecepter.This is the first reliable evidence of phytochome participationon development of haustoria in parasitic plants.
4Present address: Graduate School of Science Division of BiologicalScience, Nagoya University, Nagoya, 464-01 Japan. 相似文献
16.
Ultrastructure of Angiosperm Haustoria--A Review 总被引:2,自引:0,他引:2
It has been clear for many years that the evolution of parasitismin the angiosperms has taken place independently in a numberof unrelated groups (Kuijt, 1969). In other words, the parasiticorgans (haustoria) which both structurally and physiologicallyjoin host and parasite are remarkable instances of convergentevolution in these different groups. The main thread which canbe followed throughout the many anatomical studies which inthe past have been carried out on haustoria is the search forcommon denominators between various groups; that is, as to howmuch the haustoria of unrelated taxa have come to resemble eachother. When Solms-Laubach (18671868) more than a century agoreviewed the structure of angiosperm haustoria it required wellover one hundred pages to do so. Needless to say the bulk ofour present knowledge has been obtained since that time, andlight microscopy continues to unearth significant new information.In a recent review of haustorial anatomy (Kuijt, 1969), severalstructural parallelisms are noted. The advent of electron microscopyhas, since the latter review, resulted in a great deal of additionalinformation which has enabled certain comparisons between groupsto be made. Ultrastructural studies have quite naturally concentratedon the most readily available which, of course, are also thosewhich have been most i ntensively studied with the light microscopein the past. The haustoria of several families, such as Rafflesiaceae,Balanophoraceae, Hydnoraceae, and Lennoaceae, have scarcelybeen studied even with the light microscope. The purpose of the present paper is to give a general reviewof present knowledge of the ultrastructure of haustoria. Todo so we must of necessity ignore most recent purely anatomicalwork, except where relevant to the topics under discussion.Ultrastructural observations have been made on mistletoes (Arceuthobiumand Phthirusa, Loranthaceae), Santalaceae (several genera),Scrophulariaceae(Castilleja), Orobanchaceae (Orobanche) andConvolvulaccae (Cuscuta), in which order the discussion willproceed. 相似文献
17.
Flowering in the short-day plant Lemna paucicostata 6746 canbe induced under continuous light by the addition of ferricyanie,ferrocyanide or KCN to M-sucrose medium. Each substance is nearly10 times more effective when the flasks are covered by glassbeakers than when cotton plugs are used. By contrast, when floweringis induced under continuous light by copper or by short-daytreatment, neither flowering nor growth are affected by whetherglass beakers or cotton plugs are used. Ferricyanide, ferrocyanideand KCN are also able to induce long-day flowering when theplants are grown on Msucrose medium in small beakers that areplaced in a covered storage dish that also contains a solutionof one of these compounds. Addition of a KOH trap to the storagedish completely blocks the flowering induced by these compounds.If [14C]ferrocyanide is added to the storage dish both the M-sucrosemedium and the plants contain significant amounts of radioactivity,the amount of radioactivity being proportional to the floweringresponse. These results indicate that ferricyanide, ferrocyanideand KCN break down to release HCN and that it is the HCN whichis responsible for inducing flowering in L. paucicostata 6746under continuous light.
1Present address: Department of Biology, Osaka Kyoiku University,Ikeda, Osaka 563, Japan.
2Present address: Institute of Horticulture, The Volcani Center,P. O. B. 6, Bet-Dagan, Israel. (Received January 17, 1983; Accepted March 24, 1983) 相似文献
18.
The foraging behavior of granivorous rodents and short-term apparent competition among seeds 总被引:1,自引:1,他引:0
The foraging behavior of a predator species is thought to bethe cause of short-term apparent competition among those preyspecies that share the predator. Short-term apparent competitionis the negative indirect effect that one prey species has onanother prey species via its effects on predator foraging behavior.In theory, the density-dependent foraging behavior of granivorousrodents and their preference for certain seeds are capable of
inducing short-term apparent competition among seed species.In this study, I examined the foraging behavior of two heteromyidrodent species (family Heteromyidae), Merriam's kangaroo rats(Dipodomys merriami) and little pocket mice (Perognathus longimembris).In one experiment I tested the preferences of both rodent speciesfor the seeds of eight plant species. Both rodent species exhibiteddistinct but variable preferences for some seeds and avoidanceof others. However, the differences in preference appearedto have only an occasional effect on the strength of the short-term
apparent competition detected in a field experiment. In anotherexperiment, I found that captive individuals of both rodentspecies had approximately equal foraging effort (i.e., timespent foraging) in patches that contained a highly preferredseed type (Oryzopsis hymenoides) regardless of seed density
and the presence of a less preferred seed type (Astragalus cicer)in the patches. The rodents also harvested a large proportionof O. hymenoides seeds regardless of initial seed density;this precluded a negative indirect effect of A. cicer on O.hymenoides. But there was a negative indirect effect of O.hymenoides on A. cicer caused by rodents having a lower foragingeffort in patches that only contained A. cicer seeds than inpatches that contained A. cicer and O. hymenoides seeds. Theindirect interaction between O. hymenoides and A. cicer thusrepresented a case of short-term apparent competition thatwas non-reciprocal. Most importantly, it was caused by theforaging behavior of the rodents. 相似文献
19.
Ripe coffee seeds (Coffea arabica L.) contain large quantitiesof the purine alkaloid caffeine and the depside chlorogenicacid (5-O-caffeoyl-quinic acid). Directly after germination,both compounds were recovered almost exclusively in the cotyledonsand surrounding endosperm and hardly at all in the hypocotyland root of coffee seedlings. During the first 10 weeks of development,the cotyledons invaded the endosperm and expanded. The caffeinecontent in the developing cotyledons changed little, but thechlorogenic acid content dropped to one-third of the originallevel. The loss of chlorogenic acid was not recovered in theother organs of the seedling. The drop in chlorogenic acid contentcoincided with an increase in the amount of cell wall-boundphenolic polymers in the developing cotyledons, which couldbe extracted after thioglycolic acid derivatization. In thedeveloping cotyledons, phenylalanine ammonia lyase (PAL) activitywas hardly detectable. These results suggest that the chlorogenicacid stored in coffee seeds is used for the deposition of phenolicpolymers, presumably lignin, in cotyledonary cell walls duringexpansion. The situation in cotyledons was found to be in markedcontrast to that in foliage leaflets, in which PAL activitywas 900-fold higher than in cotyledons. In the leaflets, bothchlorogenic acid and caffeine accumulated continuously duringleaf expansion. Key words: Coffea arabica, seedling, chlorogenic acid, caffeine 相似文献
20.
Sinapine Leakage from Non-viable Cabbage Seeds 总被引:1,自引:0,他引:1
Seeds leak many compounds during the early phases of germinationand seed viability may be associated with differential leakageof specific compounds. Leakage of a fluorescent compound fromnon-viable cabbage (Brassica oleracca var. capitata L.) wasdocumented and studies were performed to identify the fluorescentcompound. Imbibed samples of both heat-killed (HK) and viablecabbage seeds were submerged in a viscous colloidal gel. After2 h to 4 h, a fluorescent halo was observed under U.V. lightaround the heat-killed seed but not around the viable seed.Viable and HK seeds were imbibed in water for 8 h and the pHof the leachate was adjusted to either 7 or 10. The absorptionspectra of leakage from HK seeds revealed peak values at 322nm and 388 nm at pH 7 and 10, respectively. This pattern wasnot observed from viable seed leakage. Two-dimensional paperchromatography was conducted on the HK seed leachate. Four fluorescentspots were observed after development first with BAW (n-butanol:acetic acid: water, 4: 1: 5 by vol.) followed by 6% acetic acid.One of the fluorescent spots (spot 3) was studied further dueto its observed intensity. Sinapine thiocyanate was preparedfrom rapeseed oilmeal and used as a reference sample. Absorptionspectra of spot 3 and sinapine thiocyanate were similar at bothpH 7 and 10. Spot 3 had identical RF values using three solventsystems and identical colour reactions in five tests comparedto sinapine thiocyanate. It was concluded that sinapine wasthe major compound responsible for the fluorescent leakage fromHK cabbage seeds. Key words: Leachate, viability, Brassica 相似文献