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1.
Buddhi Marambe Siril Wijesundara Kushan Tennakoon Dhammika Pindeniya Chandana Jayasinghe 《Weed Biology and Management》2002,2(2):79-83
The growth and development of Cuscuta chinensis Lam., and the effects of the holoparasite on the growth and yield of tomato ( Lycopersicon esculentum ), chilli ( Capsicum annuum ) and rice ( Oryza sativa ) were investigated in pot experiments under glasshouse conditions. 'Mature' and 'immature' seeds of C. chinensis showed 15 and 47% germination, respectively. The independent life duration of seedlings from 'immature' seeds was 6 days shorter than 'mature' seeds (19 days). Cuscuta chinensis formed haustoria on chilli and tomato, but not on rice seedlings. Infection with three C. chinensis seedlings per host plant reduced leaf area, dry weight, carbon and nitrogen content by 78–84% and 27–44% in tomato and chilli plants, respectively. Dry weight of C. chinensis was 0.63 g per pot in tomato, and 0.24 g per pot in chilli. Carbon and nitrogen content of C. chinensis was 0.189 and 0.028 g per pot, respectively, when grown with tomato. When it was grown with chilli, the carbon and nitrogen content of C. chinensis was 0.001 and 0.007 g per pot, respectively. Cuscuta chinensis reduced the fruit yield of tomato and chilli by 72 and 29%, respectively. The results indicated that tomato is a preferred host of C. chinensis compared with chilli, and rice is not preferred. In the host–parasite associations, C. chinensis suppressed growth and yield of chilli and tomato by diverting the elaborated products of metabolism of the hosts. 相似文献
2.
Arnoldi A Dallavalle S Merlini L Musso L Farina G Moretti M Jayasinghe L 《Journal of agricultural and food chemistry》2007,55(20):8187-8192
A series of N-mono- or N, N-disubstituted [2-(2,4-dichlorophenyl-3-(1,2,4-triazol-1-yl)]propylamines and N-[2-(2,4-dichlorophenyl-3-(1,2,4-triazol-1-yl)propyl]amides were synthesized and tested for their fungicidal activity in vitro and in vivo against a group of plant pathogenic fungi. Some compounds exhibited a fairly good in vitro activity. The replacement of the ether group of tetraconazole with a secondary or tertiary amino group leads to compounds that maintain the antifungal activity on several phytopathogenic fungi, provided that the substituents are not too bulky or lipophilic. The allyl, propargyl, and cyclopropyl groups appear particularly suitable. Although these compounds have some structural similarities with terbinafine and naftifine, which act as squalene epoxidase inhibitors, they maintain the usual mechanism of action of the other triazoles. 相似文献
3.
Jayasinghe C Gotoh N Aoki T Wada S 《Journal of agricultural and food chemistry》2003,51(15):4442-4449
The antioxidant activity of a methanolic extract of Ocimum basilicum L. (sweet basil) was examined using different in vitro assay model systems. The crude extract was fractionated on a Sephadex LH-20 column, and six fractions were identified. The DPPH scavenging assay system and the oxidation of the soy phosphotidylcholin liposome model system were used to evaluate the antioxidant activity of each fraction. Fraction IV showed the strongest activity followed by fractions V and VI. Phenolic compounds responsible for the antioxidative activity of the fractions were characterized by atmospheric pressure chemical ionization liquid chromatography-mass spectrometry. The major antioxidant compound in fraction IV was confirmed as rosmarinic acid by (1)H NMR and characteristic fragmentations in the mass spectrum. Moreover, the native of antioxidant activity of rosmarinic acid in the liposome system was examined. The results showed that one rosmarinic acid can capture 1.52 radicals, and furthermore, the existence of a synergistic effect between alpha-tocopherol and rosmarinic acid was revealed. 相似文献
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5.
M.?C.?M.?IqbalEmail author U.?L.?B.?Jayasinghe H.?M.?T.?B.?Herath K.?B.?Wijesekara Y.?Fujimoto 《Phytoparasitica》2004,32(2):119-126
Ageratum conyzoides L. is an annual herb in the tropics and subtropics whose extracts are known to possess pharmacological and biocidal activity.
We report on the bioactivity of a secondary metabolite (a chromene) isolated from the shoots ofA. conyzoides against some plant pathogenic fungi. Organic solvent extracts from the shoots were tested for antifungal activity against
the plant pathogenic fungiRhizoctonia solani, Sclerotium rolfsii, Botryodiplodia theobromae, Phomopsis theae andFusarium species growingin vitro on potato dextrose agar medium. The cruden-hexane extract completely inhibited the growth ofR. solani andS. rolfsii. Then-hexane extract was chromatographed over a column of silica gel followed by activity-guided fractionation to give an antifungal
principle. Structure elucidation by detailed analysis of1H,13C NMR and mass spectroscopy identified the active compound as precocene II. The growth ofR. solani andS. rolfsii was completely inhibited by precocene II at a concentration of 80–100 ppm. The sclerotia ofR. solani andS. rolfsii were also completely suppressed by 150 ppm of precocene II. Sub-culture of these inhibited fungi onto precocene II-free medium
restored growth of the fungus, indicating that precocene II is fungistatic. Crude or refined extracts fromA. conyzoides offer the possibility of biocontrol of plant pathogenic fungi.
http://www.phytoparasitica.org posting Feb. 11, 2004. 相似文献
6.
Evaluation of screening methods against Corynespora leaf fall disease of rubber (Hevea brasiliensis)
Fernando T. H. P. S. Jayasinghe C. K. Wijesundera R. L. C. Silva W. P. K. Nishantha E. A. D. N. 《植物病害和植物保护杂志》2010,117(1):24-29
Journal of Plant Diseases and Protection - Identification of resistant clones is a major strategy in the management of Corynespora leaf fall disease (CLFD) of rubber. Several methods to identify... 相似文献
7.
Rajesh Kumar Kharwar Vaishali Singh Chandana Haldar 《Anatomia, histologia, embryologia》2020,49(4):457-463
The role of circulatory steroid hormone along with melatonin in lung of any seasonally breeding bird has never been explored so far. This could be interesting because steroid hormones are immunosuppressive while melatonin is immunostimulatory in nature. In our present study, we report the effect of exogenous melatonin and testosterone on expression of melatonin receptor subtypes (Mel1a and Mel1b) and androgen receptor in lung of a tropical bird Perdicula asiatica. Birds were collected from vicinity of Varanasi and acclimatized in laboratory with sufficient food and water. The birds were treated with melatonin and testosterone at dose of 25 µg/100 g B.wt./day and 1 mg/100 g B.wt./day, respectively, for 28 days. At the end of the experiment, the birds were sacrificed and lung tissue and blood sample were collected for immunohistochemistry, Western blot analysis and hormonal assay. Testosterone treatment increased circulatory testosterone and upregulated expression of androgen receptors whereas downregulated expression of melatonin receptor subtypes Mel1a and Mel1b. Melatonin administration increased peripheral melatonin and upregulated expression of melatonin receptor subtypes Mel1a and Mel1b while downregulated androgen receptor. Thus, our results suggest that a trade-off relationship between melatonin and testosterone exists in regulation of their receptors in lung of Perdicula asiatica. 相似文献
8.
G. Y. Jayasinghe 《Journal of plant nutrition》2013,36(10):1441-1456
Synthetic aggregates (SA) were developed as alternative potting media for ornamental plant production. Four different types of SA were developed from low productive acidic soil and paper waste with adding different types of compost amendments. Compost amendments used in the experiment were cattle manure compost, chicken manure compost, and leaf manure compost. Popular ornamental plant french marigold (Tagetes patula) was used in this experiment. SA with different compost amendments gave considerable physical and chemical parameters compared to commercial zeolite media. Moreover, plant grown in SA media showed better growth and nutritional parameters compared to plant grown in zeolite media. The plant height, number of flowers per plant, shoot fresh weight, shoot dry weight, root length, root fresh weight and root dry weight obtained from three different compost based SA were increased by in the ranges of 8.14--14.41%, 5.66--9.46%, 25.52--31.47%, 9.44--16.13%, 6.14--9.23%, 2.40--8.47% and 8.85--17.05%, respectively, compared to zeolite control. 相似文献
9.
Arsenic (As), one of the most harmful toxicant at the global level, severely affects plant metabolism when taken up. Interestingly, the presence of silicon (Si) as a fertilizer in As-contaminated soil is an effective strategy to decrease As accumulation in plants. Brassica juncea (var. Varuna) were grown hydroponically to investigate the role of Si at biochemical and molecular levels under arsenite (As3+) stress. Seedlings of B. juncea were exposed to As3+, Si, and a combination of both elements. Our data demonstrated that seedlings exposed to As3+ showed an inhibition in shoot length, chlorophyll, carotenoid, and protein, while co-application of Si improved these growth parameters. Silicon supplementation reduced As accumulation in shoot. Increase/decrease was observed in stress-related parameters (cysteine and proline), antioxidant enzymes (superoxide dismutase, ascorbate peroxidase, and catalase), and oxidative stress markers (malondialdehyde and H2O2), which were improved upon co-application of Si as compared to As3+ alone treatment. Random amplified polymorphic DNA (RAPD) is a suitable biomarker assay for plants for assessing the genotoxicity. Seven RAPD primers produced a total of 39 and 48 bands in the leaves of the untreated and treated seedlings, respectively. The RAPD band-profiles and genomic template stability were consistent with other growth and physiological parameters. In conclusion, the genotoxic alterations along with the biochemical parameters indicate that the exposure to Si mitigates As3+-induced oxidative stress by improving the stress-related parameters and antioxidant system in B. juncea. 相似文献
10.
Vithanage I. S. Komala Yakandawala D. M. D. Maharachchikumbura S. S. N. Jayasinghe L. Adikaram N. K. B. 《European journal of plant pathology / European Foundation for Plant Pathology》2021,161(4):837-846
European Journal of Plant Pathology - Anthurium is an ornamental flowering plant, cultivated in tropical and sub-tropical climates. Anthracnose is a major disease in anthurium, known to be... 相似文献