首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 968 毫秒
1.
Fully expanded leaves of Erythroxylum coca var. coca Lam. (Erythroxylaceae)35-70-d-old were harvested from 21-month-old plants grown undergreenhouse conditions. Each harvested leaf was placed on a plexiglasssilhouette according to its dimensions and divided into fourprimary sections (petiole, base, mid and anterior) and threesubsections (lamina periphery, false mid-rib, and true mid-rib)to determine the distribution and content of hygrine, cuscohygrine,trans-cinnamoylcocaine, cis -cinnamoylcocaine, tropacocaine,tropinone, methyl ecgonine and cocaine. The leaf sub-sectionsand petiole were extracted and analysed for alkaloid content(%) by HPLC (cocaine alkaloid only) gas chromatography and GC/MS.Cocaine, methyl ecgonine and hygrine were highest in the laminaperiphery with a content of 0·48, 0·46 and 0·32%,respectively. Trans-cinnamoylcocaine was pre-eminent of thecinnamoylcocaines and was most abundant in the petiole at acontent of 0·24%. Cis-cinnamoylcocaine, tropinone, cuscohygrineand tropacocaine were ubiquitously distributed throughout theleaf where the average contents were 0·14, 0·004,0·16 and 0·04%, respectively.Copyright 1995, 1999Academic Press Alkaloids, Erythroxylum coca var. coca, E. coca, leaf alkaloids, petiole alkaloids, cocaine, cuscohygrine, methyl ecgonine, hygrine, tropinone, tropacocaine, trans-cinnamoylcocaine, cis-cinnamoylcocaine  相似文献   

2.
PLOWMAN  T.; RIVIER  L. 《Annals of botany》1983,51(5):641-659
The dried leaves of 31 species and two varieties of the genusErythroxylum were quantitatively analysed for cocaine and bothcis- and trans-cinnamoylocaine, using a stable-isotope dilutionmethod and gas chromatography-mass spectrometry selected-ionmonitoring. Both cocaine and cinnamoylcocaine were detectedin all four varieties of cultivated coca (E. coca var. coca,E. coca var. ipadu, E. novogranatense var. novogranatense andE. novogranatense var.truxillense). Cinnamoylcocaines (cis andtrans) were found in much higher concentrations in both varietiesof E. novogranatense than in either variety of E. coca. Amazoniancoca (E. coca var. ipadu) contained consistently lower cocainelevels than the montane variety (E. coca var. coca). Twenty-ninewild species of Erythroxylum, selected to represent morphological,ecological and taxonomic diversity, were analysed for the samealkaloids; cocaine was detected in 13 neotropical species, representingfive sections of the genus. No cocaine was detected in the OldWorld species. Two wild species from Venezuela, E. recurrensand E. steyermarkii, contained cocaine levels comparable tothose found in the commercially cultivated species. Erythroxylaceae, Erythroxylum, coca, cocaine, cinnamoylcocaine, alkaloids, chemotaxonomy  相似文献   

3.
A sequential study describing the content (%) of alkaloids inleaves of Erythroxylum coca var. coca Lam. from leaf bud developmentto leaf drop has not previously been conducted. The length oftime the leaf resides on the plant and its concurrent metabolicactivity also has not been defined. In the present study, cocaine,methyl ecgonine, hygrine, tropinone, trans -cinnamoylcocaine,cis-cinnamoylcocaine, tropacocaine and cuscohygrine were monitoredto determine: (1) their content and patterns of accumulationfrom leaf bud to leaf drop; (2) the time leaves resided on theplant; and (3) whether leaves were metabolically active untilleaf drop. E. coca plants were grown in a controlled environmentfor 37 months. Leaves similar in chronological age were extractedand analysed for alkaloid content by gas chromatography (GC)and gas chromatography/mass spectrometry (GC/MS). Cocaine washighest in 7 d old rolled leaves (0·75%) and declinedto 0·39% at leaf drop. Cocaine, methyl ecgonine, hygrine,tropinone, trans -cinnamoylcocaine, cis-cinnamoylcocaine, cuscohygrineand tropacocaine content in 35 d old (mature) leaves was 0·61,0·59, 0·68, 0·08, 0·31, 0·55,0·52, and 0·05%. respectively. Cocaine, methylecgonine, hygrine, cis -cinnamoylcocaine, and cuscohygrine displayeda gradual decline from week 2 to week 36 of leaf duration. Tropinoneand tropacocaine were the least abundant of the alkaloids monitored.Cis-cinnamoylcocaine content exceeded cocaine at week 12, 16,and weeks 19 to 23 of leaf duration. Trans -cinnamoylcocainewas highest in rolled leaves (week 1) and in expanded leavesafter week 30. The monitored alkaloids appeared to be part ofthe metabolically active pool of the leaf. Leaves remained onthe E. coca plants for 36 weeks.Copyright 1994, 1999 AcademicPress Cocaine, methyl ecgonine, hygrine, tropinone, trans-cinnamoylcocaine, cis-cinnamoylcocaine, cusco-hygrine, tropacocaine, leaf bud, rolled leaves, expanded leaves, alkaloids, patterns, fluctuation, Erythroxylum coca var. coca, E, coca  相似文献   

4.
Thirteen South American species of Erythroxylum have been analyzed for their cocaine content. Cocaine was found only in E. coca Lam., E. novogranatense (Morris) Hieron. and E. novogranatense var. truxillense (Rusby) Machado. The amount of cocaine was determined by mass fragmentography using deuterium labelled cocaine as internal standard  相似文献   

5.
6.
POWELL  ALISON A. 《Annals of botany》1989,63(1):169-175
Comparisons of five pairs of isogenk lines of peas, differingonly in the A gene for seed coat colour showed that white seeds(genotype aa) imbibed more rapidly than coloured seeds (AA),suffered greater imbibition damage revealed by dead tissue onthe cotyledons, and higher solute leakage. Seed-coat pigmentationwas closely associated with slow water uptake, since when expressionof the A gene was suppressed by the recessive pollens gene,the resulting white seeds {palpal AA) imbibed rapidly. The slowwater uptake by coloured seeds was not due to the restrictionof water entry by the seed coat since the differences in imbibitionrate were maintained when a portion of the seed coat was removedand seeds were imbibed with the exposed cotyledon in contactwith moist filter paper. Imbibition of similarly treated seedsby immersion in polyethylene glycol solutions (1–4%) whichincreased the seed/solution wettability, had little effect onthe water uptake of coloured seeds compared to imbibition inwater whereas that of white seeds increased in the first 10mins imbibition. Poor wettability of the inner surface of colouredseed coats did not therefore explain the slow imbibition ofthese seeds. The white seed coats loosened rapidly during imbibitionwhilst the coloured seed coats remained closely associated withthe cotyledons suggesting that the adherence of the seed coatto the cotyledons and therefore the ease of access of waterbetween the testa and cotyledons determines the rate of imbibition.The rapid water uptake by white-coated seeds and the subsequentimbibition damage may explain the high incidence of infectionof these seeds by the soil-bome fungus Pythhan after 2 d insoil. Improved seed quality and emergence may therefore be achievedby breeding for seed coat characteristics leading to reducedrates of imbibition Pisum sativum, isogenic lines, A gene, seed coat colour, imbibition, imbibition damage, wettability, pollens gene, seed quality, grain legumes  相似文献   

7.
Dissociability of the monomer ribosomes prepared from dry and imbibed pine (Pinus thunbergii) seed embryos was analyzed in sucrose density gradient containing a high salt buffer. Abnormal dissociation into the subunits was observed with the ribosome preparation from dry seed embryos when compared with that from imbibed seed embryos, i.e. each subunit peak was broader and localized at a lower site in sucrose density gradient. This indicates some change(s) in ribosomes during imbibition of seeds. These ribosomal changes also progressedin vitro. That is, after incubation of ribosome preparation from dry seed embryos in a high salt buffer for 5 min at 30 C or in a low salt buffer for 15 hr at 0 C, complete dissociation into the normal subunits was observed. No difference was found between polyacrylamide gel electrophoresis patterns of ribosomal RNA from dry and imbibed seed embryos. These results suggest some alteration in the protein components of ribosome during imbibition of pine seeds. This paper is dedicated to Prof. Shyogo Sawamura, Utsunomiya University on his retirement in March, 1979.  相似文献   

8.
Purported ‘Amazonian coca,’ Erythroxylum coca var. ipadu Plowman (E. coca var. ipadu) was harvested from cultivated fields in Colombia, South America to determine: (a) its identity; (b) if its leaf flavonoids were complimentary to those present in leaf tissue of Ec. var. ipadu in our collection derived from Colombia; and (c) if complimentary, indicative of kinship to E. coca var. ipadu obtained from Colombia, or a related Erythroxylum taxon. Leaf extracts from Amazonian field-grown coca afforded eight O-conjugated flavonoids: two O-conjugates of taxifolin, one O-conjugate of quercetin, two O-conjugates of eriodictyol and three O-conjugates of kaempferol. Present also in leaf tissue of Amazonian field-grown coca, but lacking in leaf tissue from our collection of E. c. var. ipadu was an O-ethyl ester typically found in E. coca var. coca, kaempferols and a 7-O-rutinoside commonly encountered in the E. novogranatense taxons. Flavonoids found in our collection of E. coca var. ipadu were five O-conjugated derivatives of taxifolin and an O-conjugated quercetin. Leaf flavonoids of currently cultivated Amazonian coca are a mixture of those present in E. coca var. coca, E. coca var. ipadu and E. novogranatense var. truxillense, whereas those present in our authenticated living collection are derivatives of E. coca var. coca. Our data suggest that the Amazonian coca under cultivation in Colombia is a genetic hybrid cross between E. coca var. coca and E. novogranatense var. truxillense, occurring after 1972.  相似文献   

9.
MOTT  J. J.; McCOMB  A. J. 《Annals of botany》1975,39(5):1071-1075
Seeds of Helipterum craspedioides require light for germination,and this may be given while the seed is not fully imbibed. Removalof the seed coat, or leaching, does not bring about germinationin the dark. Gibberellin enhances dark germination to some extent,whether or not the seed coat is removed. The light requirementtherefore resides in the embryo. Fresh seed is dormant in lightor dark. Excised embryos of these dormant seeds grow slowly,rarely giving mature plants, but a larger number of normal plantsis produced after gibberellin treatment. Dormancy is lost afterhigh temperature storage, but not stratification.  相似文献   

10.
The conditions and requirements of an in vitro protein-synthesizingsystem in the embryos of Pinus thunbergii seeds were studied.Even in the dry seed embryos, the ribosomes retained their syntheticcapacity. Even after imbibition in the dark, the ribosomes didnot show an increase in the activity of protein synthesis. Anincrease in the activity during dark imbibition was found inthe 100,000?g supernatant fraction. The activities of the cell-freesystems prepared from both embryos of dark-imbibed and dry seedswere dependent on the addition of poly U. This suggests thelack or inactivity of messenger RNA in these seed embryos. 1 Present address: Faculty of Education, Utsunomiya University,Mine-machi, Utsunomiya 320, Japan. (Received July 19, 1976; )  相似文献   

11.
Proteolytic Activities in x Haynaldoticum sardoum Seeds of Different Ages   总被引:1,自引:0,他引:1  
Carboxypeptidase, aminopeptidase and proteinase activities weremeasured in endosperms from dry and germinating x Haynaldoticumsardoum naturally aged seeds. Carboxypeptidase activity, presentin dry seeds, decreased slightly during germination and remainednearly unchanged during the storage period. Aminopeptidase activityincreased during germination in younger seeds, but decreasedin non-viable seeds. Proteinase activity was absent in dry seeds,increased during germination in younger seeds and disappearedin the older ones. Proteinase activity was not recovered in old endosperms followingtransplantation of young embryos, and was recovered only toa very small extent in young endosperms following transplantationof old embryos. Young endosperms onto which young embryos hadbeen transplanted gave maximum recovery of enzyme activity,although this was lower than in young intact seeds. These results suggest that the reduced or delayed availabilityof nutrients to the embryo axis is not the only factor causingthe failure of seeds to germinate, the ageing process beinga progressive phenomenon affecting both embryo and endosperm. x Haynaldoticum sardoum, Denti de cani, seed ageing, proteolytic activities, embryo-transplantation  相似文献   

12.
Dissociation of ribosomes and seed germination   总被引:1,自引:1,他引:0       下载免费PDF全文
Ribosomes from rice embryos (Oryza sativa) were dissociated into ribosomal subunits in vitro by systematic reduction of the Mg2+ concentration. Ribosomes from imbibed (28 C) embryos were more easily dissociated than those from nonimbibed embryos. This was not observed with ribosomes from either imbibed, nonviable embryos, or from embryos imbibed at 0 C. Ribosomes from embryos which had been imbided and subsequently dehydrated resembled ribosomes from nonimbibed embryos in their resistance to dissociation. The change in the resistance to dissociation was essentially complete after the first 20 minutes of imbibition at 28 C, and accompanied activation in vivo of protein synthesis as determined by amino acid incorporation in vitro. Ribosomes from either imbibed or nonimbibed embryos could be dissociated into subunits by 0.5 m KCl. These subunits were separated by density gradient centrifugation, and, if recombined, were active for polyphenylalanine synthesis in vitro. The individual subunits prepared from nonimbibed embryos could be replaced by the corresponding subunit fraction from imbibed embryos without loss of capacity to support polyphenylalanine synthesis. The change in the ease of dissociation of ribosomes appears to be a physiological process, and its possible relationship to the initiation of protein synthesis during seed germination is discussed.  相似文献   

13.
Zygotic embryos of taro, Colocasia esculenta var. antiquorumwere examined using both light and scanning electron microscopyand cultured on Linsmaier-Skoog (LS) medium without the additionof growth regulators. Embryos present within mature seed consistof a hypocotyl-root axis and an undeveloped cotyledon and aresurrounded by two major types of endosperm cells, aleurone andstarchy endosperm. Embryos cultured on LS medium developed intomature plants only in the presence of endosperm tissue. Excisedembryos turned green after 2–4 d in culture and reacheda rapid growth period between days 4 and 6. Culture of taroembryos leading to viable plantlet development depends upon(1) removal of the outer and inner integument, and (2) the presenceof endosperm tissue (including an intact aleurone layer). Colocasia esculenta var. antiquorum, Araceae, taro, embryo culture, integument, endosperm  相似文献   

14.
Larvae of the lymantriid moth Eloria noyesi, which are obligate feeders on Erythroxylum coca, excrete most of the ingested cocaine as unchanged base. Cocaine, analysed by mass fragmentography, is readily, detectable in the blood of larvae and is presumably sequestered during larval feeding, since it is present in the bodies of adult moths that do not feed on E. coca. Cocaine is an effective feeding deterrent for the ant Monomorium pharaonis when present at a concentration below that found in the leaves of E. coca.  相似文献   

15.
GILDENHUYS  P.; BRIX  K. 《Annals of botany》1965,29(4):709-715
In the interspecific cross [diploid Pennisetum typhoides X hexaploid(P. typhoides X P. purpureum)] X diploid P. typhoides, embryosand endosperms in the same ovule may respond differently totreatment with the growth substance gibberellic acid, as maydo different genotypes. Size of embryo and size of its endospermare positively correlated in some genotypes but not in others.Large fully developed normal embryos may be associated withnormal, retarded, degenerate or even no endosperm at all. Conversely,large normal endosperms, even in mature seeds, may contain large,small, or no embryos. Fully developed embryos may be viableregardless of whether they had been associated with normal,retarded or degenerate endosperm, or even no endosperm at all. It is concluded that the embryo is not always dependent on theendosperm during its early development and that a degeneratingendosperm need not have a detrimental effect on the developmentof its embryo or on the viability of the latter.  相似文献   

16.
Endogenous cytokinin and gibberellin-like activity were measuredby bioassay in developing fruit of the orchid Epidendrum ibaguense.Cytokinins decline during the first 30 d after pollination,then begin to accumulate, with very high levels (1–13µ g zeatin eq. g–1 dry wt. ) in the mature fruitand seed. The major structural change in developing fruit duringthe first 30 d is the ongoing cell division in the fruit wall.By day 30 most ovules have been fertilized and embryo developmentbegins. The increase in cytokinin activity thus coincides withthe onset of embryo development. Gibberellin levels declinein the fruit throughout development, although high activity(0.9 µ g GA3 eq. g–1 dry wt. ) is observed in themature seed. The mature embryo shows no obvious structural differentiationinto embryonic axis and cotyledon and no endosperm develops.  相似文献   

17.
Levels of ATP in dry caryopses of wild oats (Avena fatua L.)were much lower than in imbibed seeds of the seven geneticallypure lines surveyed. The ATP content of the lines with highgenetic dormancy was consistently lower than the ATP contentof genetically non-dormant lines, but no significant correlationwith depth of dormancy was found apart from this. Massive increasesin ATP content occurred within 30 min of water uptake by caryopsesof both dormant and non-dormant lines. The synthetic pathwaystudied utilized inorganic phosphate with great avidity to formATP. The ability to form ATP upon imbibition was present inboth embryo and de-embryonated caryopsis. The ATP levels attainedin imbibing caryopses appeared sufficient to support considerablesynthetic activity, and this reduced the possibility that adeficiency in ATP was responsible for the maintenance of dormancyin such imbibed seeds. The low levels of inorganic phosphatein the embryos of genetically dormant lines of wild oat couldrepresent a limiting factor, if the active formation of ATPupon water imbibition resulted in a scarcity of phosphate forother reactions essential to germination. Key words: Avena fatua, ATP synthesis, Inorganic phosphorus, Seed dormancy, Germination, Water uptake  相似文献   

18.
19.
20.
Seed water content is high during early development of tomato seeds (10–30 d after pollination (DAP)), declines at 35 DAP, then increases slightly during fruit ripening (following 50 DAP). The seed does not undergo maturation drying. Protein content during seed development peaks at 35 DAP in the embryo, while in the endosperm it exhibits a triphasic accumulation pattern. Peaks in endosperm protein deposition correspond to changes in endosperm morphology (i.e. formation of the hard endosperm) and are largely the consequence of increases in storage proteins. Storage-protein deposition commences at 20 DAP in the embryo and endosperm; both tissues accumulate identical proteins. Embryo maturation is complete by 40 DAP, when maximum embryo protein content, size and seed dry weight are attained. Seeds are tolerant of premature drying (fast and slow drying) from 40 DAP.Thirty-and 35-DAP seeds when removed from the fruit tissue and imbibed on water, complete germination by 120 h after isolation. Only seeds which have developed to 35 DAP produce viable seedlings. The inability of isolated 30-DAP seed to form viable seedlings appears to be related to a lack of stored nutrients, since the germinability of excised embryos (20 DAP and onwards) placed on Murashige and Skoog (1962, Physiol. Plant. 15, 473–497) medium is high. The switch from a developmental to germinative mode in the excised 30- and 35-DAP imbibed seeds is reflected in the pattern of in-vivo protein synthesis. Developmental and germinative proteins are present in the embryo and endosperm of the 30- and 35-DAP seeds 12 h after their isolation from the fruit. The mature seed (60 DAP) exhibits germinative protein synthesis from the earliest time of imbibition. The fruit environment prevents precocious germination of developing seeds, since the switch from development to germination requires only their removal from the fruit tissue.Abbreviations DAP days after pollination - kDa kilodaltons - SP1-4 storage proteins 1–4 - SDS-PAGE sodium dodecyl sulphate-polyacrylamide gel electrophoresis - HASI hours after seed isolation - MS medium Murashige and Skoog (1962) medium This work is supported by National Science and Engineering Research Council of Canada grant A2210 to J.D.B.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号