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Trypsin enzyme activity during larval development of Litopenaeus vannamei (Boone) fed on live feeds 总被引：1，自引：0，他引：1
Larval stages of the Pacific white shrimp, Litopenaeus vannamei (Boone) were fed standard live diets of mixed microalgae from the first to the third protozoea (PZ1 to PZ3), followed by Artemia nauplii until post‐larvae 1 (PL1). Trypsin enzyme activity for each larval stage was determined using N‐α‐p‐toluenesulphonyl‐l ‐arginine methyl ester (TAME) as a substrate. Results were expressed as enzyme content to assess ontogenetic changes during larval development. Tissue trypsin content (IU µg?1 DW for each larval stage) was significantly highest at the PZ1 stage and declined through subsequent stages to PL1. This contrasts with previously observed patterns of trypsin development in Litopenaeus setiferus (Linnaeus) and other penaeid genera, which exhibit a peak in trypsin activity at the third protozoea/first mysis (PZ3/M1) larval stage. Litopenaeus vannamei larvae transferred to a diet of Artemia at the beginning of the second protozoea (PZ2) stage were significantly heavier on reaching the first mysis stage (M1) than those fed algae, while survival was not significantly different between treatments. At both PZ2 and PZ3 stages, trypsin content in larvae feeding on Artemia was significantly lower than in those feeding on algae. The rapid decline in trypsin content from PZ1 and the flexible enzyme response from PZ2 suggest that L. vannamei is physiologically adapted to transfer to a more carnivorous diet during the mid‐protozoeal stages. 相似文献
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A diverse array of wild and weedy crucifers was screened under laboratory conditions for their resistance to Lipaphis erysimi (Kaltenbach) (Homoptera: Aphididae). Among these, Brassica fruticulosa and Brassica montana were found to be the most promising. The availability of a synthetic amphiploid, AD-4(B. fruticulosa × Brassica rapa var. brown sarson) as well as a set of Brassica juncea lines carrying genomic introgressions from B. fruticulosa allowed us to investigate B. fruticulosa resistance in greater detail. This assessment was carried out along with susceptible check B. rapa ssp. brown sarson cv. BSH-1 in a series of choice and no choice experiments. The mustard aphid showed maximum preference
for feeding on BSH-1 while least preference was recorded for B. fruticulosa followed by AD-4 as evidenced by the number of aphids that settled on circular leaf bits of these genotypes 24 and 48 h after
release in a choice experiment. Brassica fruticulosa exhibited strong antibiosis against mustard aphid in no choice experiment and all the released aphids died within 5–8 days
of their release, while the maximum survival (76.7%) was recorded on BSH-1. The survival on AD-4 (40%) was significantly lower
than that on BSH-1. Almost similar trend was observed with respect to other demographic parameters of L. erysimi viz. development time, fecundity and longevity. In the screen house studies, there was no seedling mortality in B. fruticulosa and AD-4 after 30 days of aphid release while 80% mortality was observed on BSH-1. Excellent variation for aphid resistance
was recorded in B. juncea introgression lines, emphasizing heritable nature of fruticulosa resistance. The biochemical analysis suggested the possibility of high concentration of lectins to be associated with low
aphid infestation in B. fruticulosa. 相似文献
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We evaluated ten poplar clones (G-3, G-48, L-50/88, L-154/84, L-156/89, S7C8, S7C15,WSL-22, WSL-29 and Uday) for ovipositional preference and larval performance of Clostera restitura. Female moths did not show any preference with respect to clones for oviposition. Significant differences were observed for number of eggs laidon different plant parts. C. restitura laid eggs in clusters, preferably onupper surface of leaf and size of the egg cluster varied from 15 to 167eggs. Clones varied for their relative resistance and susceptibility to C.restitura. L-50/88; L-156/89 were identified as most resistant clone basedon minimum leaf consumption, whereas S7C15 was found to be most susceptible clone to C. restitura. In multiple choice experiments, no feeding preference by C. restitura larvae was detected amongst different poplar clones. After initial settlement of larvae on a particular clone, thelarvae remained confined to that clone and negligible inter-clonal movement was noticed subsequently. The fresh pupal weight was correlated negatively (r = 0.37) with percentage surface leaf area eaten and positively (r = 0.47) with length of larval period, measured on different clones. Relationship between percentage leaf area eaten and length of larval period was negative (r = 0.23). Owing to relative resistance of L-50/88 and L-156/89 against C. restitura, these clones can be recommended for plantation in defoliator prone areas in north-western India. 相似文献
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Shera P. S. Karmakar Prasun Sharma Sudendhu Kaur Rabinder Sangha K. S. 《Phytoparasitica》2021,49(4):569-578
Phytoparasitica - Transgenic crops with genes from Bacillus thuringiensis (Bt) Berliner, a soil bacterium producing δ-endotoxin that is lethal to several phytophagous insects. Concerns related... 相似文献
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K.S. Sangha 《林业研究》2011,21(1):83-86
Poplar leaf defoliator, Clostera fulgurita (Walker) larvae were reared on three Populus deltoides clones (PL1, PL5 and PL7) in the laboratory. The nutritional indices were computed for working out the relationship between food consumption and growth rate of 3rd, 4th and 5th instar larvae on three clones. The result showed that the consumption index (CI), approximate digestibility (AD), growth rate (GR), relative growth rate (RGR) and efficiency of conversion of ingested food (ECI) decreased with the increase in the age of the larvae. Efficiency of conversion of digested food (ECD) increased with increase in age of the larvae. GR and RGR varied significantly, indicating that larval development was enhanced on PL1 as compared to PL5 & PL7. The values of AD, ECI and ECD were not affected by the different clones. Feeding and growth indices could be useful to define a defoliation prediction model. 相似文献
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K.S. Sangha 《林业研究》2011,22(1):77-82
Populus suffers from multiple insect damage throughout its distributional range in northwestern India. The evaluation of various management tools was done based on the hypothesis that manipulation of insect habitat can provide tangible results. Manipulation of cultural practices, ploughing of field during December, and growing of crops (wheat, Trifolium alexandrinum and others) results in lower adult emergence, reduced leaf infestation, number of larvae and pupae per meter branch length of poplar leaf defoliators (PLD). Fallow plantations were more prone to attack of PLD than intercropped plantations. Higher incidence of Clostera restitura was recorded in southwestern dry zones due to unsuitability of the site, poor quality of irrigation water and dry weather conditions. Complete stripping of Populus trees does not occur in low temperature & high humidity, submountaneous zones of Punjab. Chemical control studies were conducted in laboratory & field conditions, and among the five insecticides tested, Profenophos 50 EC, Quinalphos 25 EC and Carbaryl 50 WP @ 0.05 and 0.1 percent concentration gave consistently high mortality of PLD larvae up to 21 days after spraying. Use of insecticides prior to peak activity periods & during evening hours enhances the efficiency of management options. 相似文献