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51.
FERNANDO ALFEREZ SHILA SINGH ANN L. UMBACH BRANDON HOCKEMA & JACQUELINE K. BURNS 《Plant, cell & environment》2005,28(11):1436-1449
The compound 5-chloro-3-methyl-4-nitro-1H-pyrazole (CMNP) is a pyrazole-derivative that induces abscission selectively in mature citrus (Citrus sinensis) fruit when applied to the canopy and has herbicidal activity on plants when applied to roots. Despite the favourable efficacy of this compound, the mode of action remains unknown. To gain information about the mode of action of CMNP, the effect of application to mature citrus fruit and Arabidopsis thaliana roots was explored. Peel contact was essential for mature fruit abscission in citrus, whereas root drenching was essential for symptom development and plant decline in Arabidopsis. CMNP was identified as an uncoupler in isolated soybean (Glycine max) mitochondria and pea (Pisum sativum) chloroplasts and an inhibitor of alcohol dehydrogenase in citrus peel, but not an inhibitor of protoporphyrinogen IX oxidase. CMNP treatment reduced ATP content in citrus peel and Arabidopsis leaves. Phospholipase A2 (PLA2) and lipoxygenase (LOX) activities, and lipid hydroperoxide (LPO) levels increased in flavedo of citrus fruit peel and leaves of Arabidopsis plants treated with CMNP. An inhibitor of PLA2 activity, aristolochic acid (AT), reduced CMNP-induced increases in PLA2 and LOX activities and LPO levels in citrus flavedo and Arabidopsis leaves and greatly reduced abscission in citrus and delayed symptoms of plant decline in Arabidopsis. However, AT treatment failed to halt the reduction in ATP content. Reduction in ATP content preceded the increase in PLA2 and LOX activities, LPO content and the biological response. The results indicate a link between lipid signalling, abscission in citrus and herbicidal damage in Arabidopsis. 相似文献
52.
A. PAVAN-KUMAR SUDHANSHU RAMAN PRAKASH G. KORINGA NAMRATA PATEL TEJAS SHAH RAJEEV K. SINGH GOPAL KRISHNA C. G. JOSHI P. GIREESH-BABU APARNA CHAUDHARI 《Journal of genetics》2016,95(4):853-863
The mahseers (Tor, Neolissochilus and Naziritor) are an important group of fishes endemic to Asia with the conservation status of most species evaluated as threatened. Conservation plans to revive these declining wild populations are hindered by unstable taxonomy. Molecular phylogeny studies with mitochondrial genome have been successfully used to reconstruct the phylogenetic tree and to resolve taxonomic ambiguity. In the present study, complete mitochondrial genome of Tor tor has been sequenced using ion torrent next-generation sequencing platform with coverage of more than 1000 ×. Comparative mitogenome analysis shows higher divergence value at ND1 gene than COI gene. Further, occurrence of a distinct genetic lineage of T. tor is revealed. The phylogenetic relationship among mahseer group has been defined as Neolissochilus hexagonolepis ((T. sinensis (T. putitora, T. tor), (T. khudree, T. tambroides)). 相似文献
53.
DIVYA DARSHAN PANT F.L.S. RITA SINGH 《Botanical journal of the Linnean Society. Linnean Society of London》1989,100(2):183-196
PANT, D. D. & SINGH, R., 1989. On the possible occurrence of anisospory in some Hepaticae. Possible anisospory is reported for the first time in four species of Hepaticae, viz., Targionia indica Udar, Targionia hypophylla L., Cyathodium aureo-nitens Griff. (Mitt.), Cyathodium barodae Chavan. The report is based on observations of wide variations in size of spores comparable with those of anisosporous mosses of the family Orthotrichacae. 相似文献
54.
Partial purification and characterization of phospholipase C from Yersinia enterocolitica 总被引:1,自引:1,他引:0
S. TOORA GAGANDEEP SINGH S. DHAR A.D. SINGH R.P. TIWARI G. SINGH 《Journal of applied microbiology》1989,66(4):303-309
About 34% of the strains of Yersinia enterocolitica isolated from raw milk were found to produce lecithinase. A selected strain produced phospholipase C at 22°C and 37°C; production was optimum at 37°C in the stationary phase (14–16 h). A decrease in phospholipase C activity at various storage temperatures (—5°C, 4°C, 37°C) was also observed, although the enzyme was active over a wide range of temperature (5–65°C) and pH (3mD5–7mD5). The phospholipase C was partially purified by ammonium sulphate precipitation and Sephadex column chromatography, and characterized. 相似文献
55.
Protoplasts from growing regions of etiolated pea stems takeup glucose more rapidly than fructose when supplied for briefperiods at low concentrations. The uptake of the two hexosesis differentially inhibited by galactoac and by reagents thatcurtail ATP synthesis, and uptake of one hexose is not preventedby the other, even at a 100-fold excess. Sucrose uptake is muchslower than that of either hexose and is correlated with theappearance of invertase activity in the medium. Label from [14C-glc]-sucroseis taken up more rapidly than from [14C-fru]-sucrose. It isconcluded that these cells take up supplied sucrose only afterhydrolysis to hexoses, which are then absorbed by differentcarrier-mediated processes. Key words: Glucose, fructose, invertase, pea, protoplast, sucrose 相似文献
56.
57.
STANLEY M. GARTLER SHI-HAN CHEN PHILIP J. FIALKOW ELOISE R. GIBLETT SURJIT SINGH 《Nature: New biology》1972,236(66):149-150
THE Lyon hypothesis of X chromosome inactivation predicts that in mammalian females, somatic cells are mosaic with respect to whether the active X chromosome is of maternal or paternal origin and that this chromosomal mosaicism is heritable somatically1. Studies of cell clones derived from females who were heterozygous for genes at one of several X-linked loci2–6 have provided good evidence for such mosaicism. Proof that only one of the two X chromosomes, however, is active in any given cell rests on the demonstration that the cell or its clone expresses all of the X-linked genes from one parent and none from the other parent. For this purpose it is useful to examine cloned cells from female subjects for genetic markers representing allelic genes at two or more of the parental loci. This study was undertaken to determine whether genes at the X-linked loci for glucose-6-phosphate dehydrogenase (G6PD) and phosphoglycerate kinase (PGK) are consistently expressed in the eis position in cloned cells as would be expected from a single parental contribution. 相似文献
58.
Nitrogen and Carbohydrate Metabolism of Japanese Mint as Affected by Phosphorus Deficiency and Seasonal Variations 总被引:1,自引:0,他引:1
The paper presents effects of phosphorus deficiency and seasonal variations on nitrogen and carbohydrate metabolism of Japanese mint (Mentha arvensis L. var. piperascens, Holmes). Mint plants were grown in sand cultures under full nutrition and under phosphorus deficiency conditions during winter and summer. Various nitrogen and sugar fractions were determined in the component parts at specified periods of growth stages. Phosphorus deficiency disturbed the nitrogen metabolism at the stages for amide and amino acid formation, which resulted in an accumulation of carbohydrates. The content of total soluble and total nitrogen was higher and that of insoluble nitrogen was lower in summer as compared with winter plants. Of the soluble fractions, the ammonia, amide and nitrate nitrogen were higher and the ‘rest’ nitrogen lower in winter plants. Nitrate formed the highest bulk of the pool of soluble nitrogen in winter, whereas in summer ‘rest’ nitrogen was most abundant. The content of total sugar in winter plants far exceeded that of summer plants, which was wholly due to increase in sucrose content. Glucose was the predominant reducing sugar in both seasons. However, the summer plants were richer in glucose than those from the winter. 相似文献
59.
The present study deals with structure and functioning of threeareas of Himalayan oak forest. Low- and mid-altitude oaks, namelyQuercus leucotrichophora, and Quercus floribunda, form predominantevergreen forests in Central and Western Himalaya. The totaltree basal cover ranged between 33·89 m2 ha1 (Q.floribunda site) to 36·83 m2 ha1 (Q. leucotrichophorasite). The density ranged between 570 and 760 individuals ha1.Allometric equations relating biomass of different tree componentsto GBH (girth at breast height) were significant with the exceptionof leaf biomass in Q. leucotrichophora and Rhododendron arboreum.Total vegetation biomass (29·40467·0 tha1) was distributed as 377·1 t ha1 intrees, 5·40 t ha1 in shrubs and 1·23 tha1 in herbs. Total forest floor biomass ranged between4·6 and 6·2 t ha1. Of the total annuallitter fall (4·74·8 t ha1), 77·5% was contributed by leaf litter, 17·8 % by wood litterand 4·7 % by miscellaneous litter. Turnover rate of treelitter varied from 0·66 to 0·70. Net primary productionof total vegetation ranged between 15·9 and 20·6t ha1 yr1, of which the contribution of trees,shrubs and herbs was 81·2 %, 8·6 % and 10·2%, respectively. A compartment model of dry matter on the basisof mean data across sites was developed to show dry matter storageand flow of dry matter within the system. Quercus leucotrichophora forest, Q. floribunda forest, Q. lanuginosa forest, biomass, litter fall, net primary production, compartmental transfer 相似文献
60.
The ontogenic changes in several component processes of photosynthesiswere measured in chickpeas. Gas exchange characteristics ofintact leaves were studied to analyse the effects of ambientconditions under which chickpeas are usually grown. The CO2assimilation rate per unit leaf area remained fairly high duringthe vegetative stage, reaching a peak at early pod-fill anddeclining subsequently throughout pod development. The intercellularCO2 partial pressure (C1) remained more or less constant (195µbar) during vegetative growth and the early stages ofseed-filling. With falling RWC and PAR interception, the stomatalconductance declined more rapidly than the CO2 assimilationrate resulting in a value of C1 less than that normally existingunder ambient conditions. From the A/C1-analysis, CO2 assimilationduring pod-filling appears to be limited by the RuBP-regenerationcapacity because the carboxylation efficiency and in vitro RuBPCaseactivity were initially unaffected. However, as leaves aged,the carboxylation efficiency and in vitro RuBPCase activitydecreased abruptly with increasing leaf temperatures above 30°C, and the C1 was greater than normally existing values(195 µbar), suggesting an increased mesophyll limitationof photosynthesis. It is suggested that a decline in the CO2assimilation rate of leaves during pod development and an acceleratedsenescence are induced by adverse ambient conditions, particularlyplant water stress and high leaf temperature. Key words: Cicer arietinum L., gas exchange, photosynthesis, ribulose-1,5-bisphosphate carboxylase 相似文献