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1.
The folypolyglutamate derivatives of pea seedlings (Pisum sativumL. cv. Homesteader) were extracted in the presence of 2-mercaptoethanoland cleaved to p-aminobenzoylpolyglutamates by treatment withZn-HCl. Azo dyes were formed by reaction with naphthylethylenediamine and purified by polyacrylamide gel chromatography. p-Aminobenzoylpolyglutamateswere regenerated from these dyes by Zn treatment and then concentratedin vacuo. These derivatives were separated according to glutamylchain length by high performance liquid chromatography on WhatmanPartisil SAX columns. The folylpolyglutamates of 4 day old peacotyledons, pea leaves and isolated chloroplasts were mainlytetra- and pentaglutamates. These and folates of shorter chainlength were labelled when seeds and aerial shoots were incubatedwith p-aminobenzoate-[14C]. Labelling of the pentaglutamatewas reduced in seeds that were imbibed in the presence of 0.1mM methotrexate. Studies of cotyledon folylpolyglutamate synthetaseshowed that polyglutamate chain length was affected by incubationtime and the concentration of tetra-hydrofolate monoglutamatein the reaction system.
1Present address: Department of Biology, University of Lethbridge,Alberta, Canada T1K 3M4
2Present address: Department of Horticulture, Xiong-yue AgriculturalCollege, Xiong-yue, Liaoning Province, China (Received August 4, 1989; Accepted December 5, 1989) 相似文献
2.
Araki Shigeru; Sakurai Takemaro; Oohusa Tuyosi; Kayama Mitsu; Sato Naoki 《Plant & cell physiology》1989,30(5):775-781
Sulfoquinovosyl diacylglycerol (SQDG) from a red alga, Gracilariaverrucosa, contained high levels of saturated fatty acids, palmiticand myristic acids. The lipid was separated by normal-phasethin-layer chromatography (TLC) into two spots which differedin terms of the color generated by the anthron reagent and interms of constituent fatty acids. However, chromato-graphicand spectrometric (NMR and IR) analyses indicated that boththe upper and the lower fractions were SQDG. The upper fractionwas mainly composed of 20:4/16:0 species, while the major speciesin the lower fraction was mainly 14:0/16:0 and 16:0/16:0. Comparisonof mobilities of SQDG from various sources by TLC confirmedthat the chain length of acyl groups significantly affectedthe Rf value. The short-chain saturated acid species of SQDGwas also detected in marine red algae, Gracilaria textorii,Gelidium amansii, Chondrus ocellatus and Chon-dria crassicaulis. (Received December 9, 1988; Accepted May 10, 1989) 相似文献
3.
Seasonal shell growth, reproduction and mortality of the eggcowry Ovula ovum were studied from May 2004 to October 2006in southern Kyushu, Japan, an area at the northern margin ofits geographic distribution. Rapid shell growth was observedduring the period of warmer ocean temperature (May–October).Average shell growth rate of small cowries was 2.84 mm/week.Reproductive activities were observed during most of the yearexcept during the coldest period (March–April). Egg cowriesreach maturity at approximately 7 cm in shell length, and at1 year of age. Average shell length of brooding females andcopulating pairs (female and male) were 8.14 ± 0.40,8.17 ± 0.49 and 8.08 ± 0.43 cm (mean ±SE), respectively. High mortality rates (average 67.5%) wereobserved from December to May. The maximum numbers of emptyshells in the field (April 2005, May 2006) were seen duringthe period of the lowest ocean temperatures (March 24, 2005;March 7, 2006). This suggests that ocean temperature may bean important factor for egg cowry populations at the northernmargins of their geographical distribution, and that O. ovummay increase fitness with rapid shell growth and early age ofmaturation. (Received 11 January 2008; accepted 22 August 2008) 相似文献
4.
When Azolla plants (Azolla filiculoides vax.japonica) were grownin media with high concentrations of ammonium ions at pH 3.5,numbers of cyanobionts in apical portions were very much reduced.Microscopic observations revealed that cyanobionts in theseplants were preferentially damaged, with resultant death andlysis. (Received August 2, 1991; Accepted December 27, 1991) 相似文献
5.
The rotifers of Warri River, Nigeria 总被引:2,自引:0,他引:2
The rotifer assemblage of the dendritic tidal Warri River wasinvestigated at four sampling points from July 1981 to July1982. Forty-one species of Rotifera were identified. Five ofthese Anuraeopsis racenesi Berzins Keratella cochlearismacracantha Lauterbom, Monostyla lunaris Pawlowsky,M. stenroosiMeissner and Trichocerca similis grandis Hauer are beingrecorded for the first time in West Africa. The Warri Riverrotifers are 65% cosmopolitan and 20% pantropical although therewas no species limited to African waters only. The dominantrotifers in the Warri River were Keratella tropica and K. cochleariswhich were found in the predominantly freshwater sampling stationat Udu Bridge to Warri and Orugbo Creek where low brackish watersalinities and conductivities are observed from December orJanuary to April each year. The preponderance and longitudinaldistribution of these two well-known cyclomorphic rotifers providesan opportunity to study their salinity tolerance and the effectof salinity and conductivity on their cyclomorphosis by samplingalong the length of the river from Udu Bridge to Forcados wherethe Warri River joins the Atlantic Ocean. 相似文献
6.
Seasonal succession and variation in species composition, density,biomass, age distribution and frequency of zooplankton (mainlythe Copepoda) were analysed during the austral summer of of1977/1978 in Ezcurra Inlet, a part of the Antarctic coastalecosystem. Small zooplankters (i.e., cyclopoids of the generaOncaea and Oithona, and calanoids Drepanopus pectinatus andScolocithricella glacialis) were found to predominate in termsof abundance and percentage contribution. The zooplankton biomasswas dominated by larger organisms of the Metrididae and Calanidae(Calanoida). The maximum abundance and maximum biomass of copepodswere recorded in February; two small peaks in copepod biomassbeing observed in late December and late January, and a lesserbiomass peak in late December. The vertical distribution ofcopepods in terms of their diel and seasonal (December, January,February, March) changes showed a day-time maximum to have occurredin the near-bottom layer, the nocturnal distribution being bimodalwith peaks within 010 m and 2550 m. The summerzooplankton community in Ezcurra Inlet is controlled by trophic(phytoplankton composition and density) and hydrological (waterexchange with Bransfield Strait) conditions prevailing in thearea. 相似文献
7.
Evidence that the anther is a source of GAs which may be a mainfactor limiting the growth of floral organs of Mirabilis jalapais presented. GAs in floral tubes at different developmentalstages were surveyed using TLC followed by bioassay with Tan-ginbozudwarf rice seedlings. The amount of GAs in the floral tube increasedrapidly after the calyx became visible above the bract 8 daysbefore anthesis, reached a maximum 5 days before anthesis, thendeclined markedly thereafter. The stamen had relatively largeamounts of GAs and mainly accounted for the change of GAs duringthe flower development. The GA content in the anther was 3 timesas much as that in the filament. Exogenously supplied GA3 promotedelongation of sections in excised flower organs. Extracts ofanthers also showed definite growth promotion of style sections.Removal of the anthers greatly reduced the final length of thefloral tube. (Received December 7, 1974; ) 相似文献
8.
Stomatal Characteristics at Different Ploidy Levels inCoffeaL. 总被引:1,自引:0,他引:1
Stomatal frequency, epidermal cell frequency, stomatal guardcell length and stomatal index were examined at different ploidylevels inCoffea. In general, stomatal and epidermal cell frequencyper unit leaf area decreased while stomatal guard cell lengthincreased with an increase in ploidy. The reduction in stomatalfrequency at higher ploidy levels was mainly a result of largerepidermal cells. In the case ofC. canephora(cultivar S.274)a significant reduction in stomatal frequency was noticed fromdiploid to tetraploid level which was due to both larger epidermalcell size and less stomatal differentiation at the tetraploidlevel. Besides the effect of ploidy on stomatal frequency andguard cell length, genotypic differences in stomatal frequencyand stomatal guard cell length were also observed among cultivarsof the same ploidy level. Although variation in stomatal frequencyamong cultivars was found to be associated with the differencein stomatal to epidermal cell ratio, variation in guard celllength was attributed to differential genetic architecture.In the present study a highly significant positive correlation(r=0.82) between stomatal and epidermal cell frequency and highnegative correlations between stomatal frequency and guard celllength (r=-0.91) and epidermal cell frequency and stomatal guardcell length (r=-0.93) were obtained. The study also indicatedthat stomatal frequency can be predicted with 83 and 87% accuracy,respectively, by measuring stomatal guard cell length in coffee.Copyright1997 Annals of Botany Company Coffea; ploidy level; stomatal characteristics 相似文献
9.
The Effects of Dwarfing Genes Rht1 and Rht2 on Cellular Dimensions and Rate of Leaf Elongation in Wheat 总被引:2,自引:0,他引:2
The gibberellin insensitivity genes, Rht1 and Rht2, reducedepidermal cell lengths in leaves of isogenic lines of field-and laboratory-grown wheat (Triticum aestivum L.). Rht dosagesof zero (wild type), two (semi-dwarf) and four alleles (doubledwarf) had a linear negative effect on cell length in flag leavesof field-grown plants, and in the sheaths and blades of leafnumber 1 in laboratory grown plants. Decrease in cell length,rather than reduced cell number, accounted for most to all ofthe reduction in blade and sheath length. In sheaths, cell widthincreased with Rht dosage, but not sufficiently to compensatefor decreased length in determining average projected surfacearea. Rates of extension of leaf number 1 in laboratory-grownplants were negatively and linearly correlated with Rht dosage.Maximal growth rate was maintained longer in wild type thanin double dwarf, but the total duration of measurable extensionin leaf number 1 was not affected by Rht dosage. Cell size, elongation, Rht, wheat, Triticum aestivum L 相似文献
10.
Four species of Pterotrachea are currently recognized,
two ofwhich (P. hippocampus Philippi, 1836, and
P. minuta Bonnevie,1920) have very similar
morphologies. These two species havebeen distinguished mainly on the
basis of eye and visceral nucleusshapes; the former with wide,
triangular eyes and a short, broadnucleus, and the latter with
narrower, triangular eyes and ataller, more slender
nucleus. Quantitative and qualitative morphologicaldata were obtained
from specimens of P. hippocampus and P. minuta
collectedduring two oceanographic sampling programs in the North
AtlanticOcean. Comparisons of eye and visceral nucleus shapes
(representedby their length to width and length to retinal width
ratios,respectively), plotted against body length showed linear
decreases,with no justification for the recognition of two separate
species.Examination of eye shape across a wide range of body sizes
showedthat the width of the retina increases disproportionately with
bodygrowth (by elongation and medial upturning) beginning at a length
ofabout 21-22 mm. As a result, the overall appearance of the eyeat
this body size changes such that smaller animals (less than21-22 mm)
have eyes corresponding with those of P. minuta, whilethe
eyes of individuals larger than this body length match thoseof
P. hippocampus. Several authors have distinguished femalesof
the two species by the presence (P. hippocampus) or absence
(P.minuta) of cuticular spines anterior to the
eyes. Examinationof female specimens showed that those less than
about 30 mmlacked these spines, while those above this size possessed
them.Thus, cuticular spines represent a secondary female sexual
characteristic. Other morphological features that have been used by
previousauthors to distinguish the two species were examined and
rejected.Because P. hippocampus was described prior to
P. minuta, itis herein regarded as the senior synonym of
P. minuta. (Received 12 June 1997; accepted 21 May 1999) 相似文献
11.
Stem cuttings of Chrysanthemum morifolium Ram. were treatedwith aqueous solutions of (2-chloroethyl)phosphonic acid (Ethrel)and indolebutyric acid (IBA). Ethrel (1 mg per 1) as a dip oras two foliar sprays, promoted root length and branching inMrs. Roy and Clipper which are difficult-to-root cultivars,but had no effect on Improved Mefo, an easy-to-root cultivar.IBA increased root number in both Clipper and Improved Mefo.The results suggest that IBA and Ethrel act at different stagesof the rooting process, with IBA promoting initiation and Ethrelstimulating elongation and branching. Increases in root numberwith IBA treatment, and in root length with Ethrel treatment,were accompanied by decreases in the soluble carbohydrate concentration,particularly in stem bases. 相似文献
12.
The population structure of Sagitta setosa from the south-westernpart of the Black Sea was examined between May 1994 and December1996. In addition, the vertical distribution and diel verticalmigration of S.setosa were studied for juveniles ( 相似文献
13.
SYNOPSIS. Four adult females of the katydid Lirometopum coronatumScudder (Orthoptera: Tettigoniidae: Copiphorinae) were collectedat night near the Old Lab building at Finca La Selva ResearchStation in Costa Rica 1214 April 1983. From laboratoryobservations, this katydid appears to be primarily nocturnaland carnivorous. These and subsequent generations (through F3)were maintained in the Insect Zoo at the San Francisco ZoologicalGarden from April 1983 to December 1985. Propagation methodswere developed. Life history and behavior data were recorded:F1 females ranged in adult body size from 46 mm to 55 mm; adultovipositor length ranged from 19 mm to 27 mm; from hatchingto death ranged from 189 to 301 days; with an average life spanof 239. Males ranged in adult body size from 41 mm to 47 mm;age ranged from 164 to 390 days; with an average life span of308 days. Both stridulation and leaf shaking was observed inmales. 相似文献
14.
Multivariate statistical methods were employed to examine
sexualdimorphism in size and shape of Nucella lapillus collected from
16sheltered sites along coasts of Anglesey and the Lleyn Peninsula,
NorthWales, UK. Females were significantly larger than males in
overallsize; among 12 relative measures of shell shape, two ratios
(shellwidth/shell length and aperture length/shell length) were
significantlydifferent between males and females, but these
differences usuallydecreased with increasing age (shell length). The
observed hypoallometricdimorphism could be a result of selection on
increased femalefecundity, which may be positively correlated with
shell sizein N. lapillus as in other gastropod species. (Received 22 November 1999; accepted 10 April 2000) 相似文献
15.
The effects on standard length of storing laboratory-rearedlarval herring (919 mm live length) in 4% buffered formaldehydeor 70% buffered ethanol with and without simulated capture bytowed net were assessed. Lengths during storage were consideredstable after 15 days for larvae placed directly in formaldehyde,and after 30 days for larvae placed directly into alcohol orfor larvae treated by net-capture simulation before storage.The following linear regressions described the relationshipsbetween live length and the stored lengths of larvae after thesetimes: for larvae stored directly in formaldehyde, L = 1.765+ 0.867 x X1 for larvae stored directly in alcohol, L = 0.564+ 0.971 x X1; for larvae subjected to net-capture simulationthen stored in formaldehyde, L = 0.984 + 0.993 x X1; and forlarvae subjected to net-capture simulation then stored in alcohol,L = 0.532 + 0.989 x X1 where L = live standard length and X1= standard length after storage. The non-linear regression formulaparameterized by Theilacker (Fish. Bull US, 78,685692,1980) for northern anchovy larvae provided a good fit to thedata for herring larvae subjected to net-capture simulationand then stored in formaldehyde. However, the model had to bere-parameterized to provide a good fit for larvae stored inalcohol. The precision achieved in length measurements usinga computer-aided measuring system is also discussed. 相似文献
16.
Laboratory experiments undertaken with the South China Sea volute,Melo melo, have shown that it is a specialized predator of othercontinental shelf predatory gastropods, notably Hemifusus tuba(Melongenidae) and Babylonia lutosa (Buccinidae). (Received 30 December 1985; 相似文献
17.
SIMONE LUIZ RICARDO LOPES DE; MORACCHIOLI NICOLETTA 《Journal of Molluscan Studies》1994,60(4):445-459
Potamolithus karsticus n. sp. and Potamolithus troglo-bius n.sp., two Brazilian aquatic cavesnails (Gastropoda: Hydrobiidae),are described. P. troglobius is blind and depigmented, and isthe first stygobiontic snail to be described from Brazil Additionally, specimens of Potamolithus ribeirensis Pilsbry,1911 were collected near the type locality for comparison withthe new cave species (Received 2 December 1993; accepted 20 June 1994) 相似文献
18.
19.
Distribution and ecology of tintinnids in the plankton of Lebanese coastal waters (eastern Mediterranean) 总被引:3,自引:0,他引:3
The tintinnids of Jounieh Bay in Lebanon were identified andtheir numerical abundance determined in horizontal and verticalnet samples from February 1979 to December 1980. Large fluctuationsin abundance and composition of the tintinnid fauna occurredduring the period of investigation. Two distinct peaks werenoted, a major one in MayJune and a minor one in NovemberDecember.The first followed the main phytoplankton peak, suggesting apositive nutritional relationship between the two populations.The most abundant species were Tintinopsis beroidea and Eutintinnuslusus-undae. A few other species showed great abundance duringshorter periods. In all, 121 species were recorded during thisperiod, and of these 12 belong to the genus Tintinnopsis and11 to Eutintinnus. 相似文献
20.
Cellana grata is a high-zoned, exposed-shore limpet with a lifespanof 3 years. Patclloida pygmaeais a low-zoned, sheltered-shorelimpet with a lifespan of I year. C. grata migrates up-shorein winter, but occurs lower on the shore in summer. This migrationis synchronized with variations in algal availability high onthe shore; such variations are, however, themselves relatedto seasonal changes in wave height. P. pygmaea is restrictedto the low shore, year round. The movements upwards in winterand downwards in summer are still evident. Algal species richnessincreased from September to reach a peak between December andMarch, and to abruptly diminish between May and June. The encrustingalgae Brachytrichia maculans, Hildenbrandia prototypus, Lithothamnionsp. and Ralfsia vcrrucosa were present year round. The timingof juvenile recruitment of C. grata and P. pygmaea was fromOctober to July and February to October, respectively. Temperaturemay be important in enhancing juvenile survival by affectingthe seasonal pattern of algal occurrence on the shore. Seasonalfluctuations in the rate of growth were recorded for both specieswith the time of fastest growth of C. grata and P. pygmaea occurringbetween October and March and September and February, respectively.Mortality of both species occurred mainly in summer. Summerheat, predation and intra-specific competition for food appearto be the major causes of death. (Received 1 December 1992; accepted 5 May 1993) 相似文献