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991.
992.
Embryonic and larval developments of brackish water catfish,Mystus gulio (Hamilton and Buchanan, 1822) induced with human chorionic gonadotropin and consequent larval rearing 下载免费PDF全文
Prem Kumar Gouranga Biswas Tapas Kumar Ghoshal Muniyandi Kailasam Koyadan Kizhakedath Vijayan 《Aquaculture Research》2018,49(7):2466-2476
Mystus gulio, the long whiskers catfish, is a popular food fish and potential candidate species for aquaculture in Sundarban area of India and Bangladesh. Recently, catch of this species has declined due to overfishing and various ecological changes. In the present study, mature fish was induced to spawn in captivity through intramuscular injection of human chorionic gonadotropin at the doses of 10 IU/g to female and 5 IU/g to male. Photomicrographs of all developmental stages of live embryo and larvae were documented with the aid of a light microscope. Results demonstrated that morula, blastula, gastrula and neurula and organogenesis ended at 1:30‐, 3:00‐, 5:30‐, 7:30‐ and 17:15‐hour post‐spawning (hps) respectively. Heartbeat and muscular contraction of embryo commenced at 8:30 and 11.15 hps respectively. Hatching of embryo started after an incubation period of 17:30 hour at an ambient temperature of 29 ± 1°C. The newly hatched larvae measured 2.17 ± 0.29 mm in total length with a yolk volume of 0.165 ± 0.03 mm3 started feeding 36 hr after hatching. The present study, on induced breeding and chronological development of M. gulio embryo, will have significant implications on conservation and seed production for aquaculture. 相似文献
993.
994.
依据岷江中游眉山~乐山河段(简称眉乐段)水质监测资料,选用具有代表性的水质因子COD、NH3-N、TP分析眉乐段水质变化趋势,探讨航电梯级开发对水质的影响.结果表明,眉乐段水质主要受上游来水影响,府河汇合后的岷江干流眉乐段区间污染负荷量相对较少,对河流水质影响相对较小;河段水质在空间分布上总体呈现上游至下游逐步好转的趋势,COD沿程稳定达到Ⅲ类水质标准,NH3-N和TP沿程降低;在时间分布上,水质逐年变好;主要支流体泉河水质较差,超标严重,思蒙河和毛河COD、NH3-N浓度维持在Ⅲ类水质标准,TP浓度超过Ⅳ类水质标准,且有逐年升高趋势;汉阳库区建成后COD、NH3-N较建成前降低,TP较建成前略微增加,汉阳库区出库COD、NH3-N、TP较入库降低.研究结果可为航电梯级水库环境影响分析?航电开发和水环境治理提供参考依据 相似文献
995.
Molecular and functional characterization of nucleoside diphosphate kinase (nm23) gene in oriental river prawn Macrobrachium nipponense during ovarian development 下载免费PDF全文
996.
采用盆栽方法研究不同浓度(2‰,4‰,6‰)中性复合盐对具有不同遗传背景的两种基因型菊芋幼苗(LZJ028有性繁殖能力强且营养品质高;LZJ017块茎产量高)生长和光合等生理特性的影响,探究不同遗传背景菊芋幼苗对盐胁迫的响应差异。结果表明:(1)当盐浓度为4‰和6‰时,两种基因型菊芋幼苗的株高、叶面积、冠幅和地上部分干物质和鲜物质积累(与对照相比)均下降,LZJ028基径、叶面积和地上部分干、鲜物质积累下降幅度(4.24%和6.26%,14.82%和29.67%,8.51%和19.68%,7.62%和22.38%)均显著低于LZJ017的降幅(9.78%和29.75%,58.33%和63.18%,15.77%和26.88%,40.62%和61.82%)。(2)随着盐浓度升高,两种基因型菊芋幼苗叶片的SOD活性、脯氨酸和可溶性糖含量均显著升高(如盐浓度为6‰时LZJ017和LZJ028的SOD活性比对照组升高了0.41倍和1.87倍;脯氨酸升高了8.26倍和42.92倍;可溶性糖含量升高了0.39倍和1.18倍),LZJ028的各指标升高幅度均较大。(3)盐浓度升高,两种基因型菊芋幼苗叶片净光合速率、蒸腾速率、气孔导度和叶绿素含量均降低,LZJ028净光合速率和气孔导度下降幅度均低于LZJ017;盐浓度升高,两种菊芋幼苗PSⅡ潜在活性和最大光化学效率也均下降,而初始荧光升高,如盐浓度为6‰时与对照相比LZJ028最大光化学效率和初始荧光变化幅度(10.53%和4.81%)低于LZJ017的变化幅度(43.04%和52.73%)。研究表明,盐胁迫主要抑制两种基因型菊芋叶片PSⅡ活性和碳水代谢速率进而抑制其生长,二者均通过提高保护酶SOD活性、增加渗透调节物质等策略缓解盐胁迫造成的伤害;LZJ028较耐盐,LZJ017对盐较敏感。 相似文献
997.
998.
Matthew D. Wilson Adelina Latinovic Noel W. Davies Peter B. McQuillan Robert C. Menary 《Journal of Crop Improvement》2018,32(3):331-352
Tasmanian Mountain Pepper is a new crop that produces a valuable flavoring agent derived from its fruit. However, annual yields are unpredictable and its commercial prospects depend upon a reliable fruit set. As poor pollination is a possible cause, the pollination biology of this dioecious plant was examined in natural and plantation settings using direct observations, sticky traps, gas chromatography, and microscopy. A community of small insects visits the flowers, and the insect species represent at least seven families of small flies, three families of beetles, and various wasps and moths. Pollen grains were observed on the bodies of bibionid flies (Bibionidae), syrphid flies (Syrphidae), and snail-flies (Sciomyzidae). The tetrahedral tetrad pollen grains are unlikely to be suitable for dispersal by wind. Similar volatiles were emitted by both males and females; several ocimene compounds are attractants for insect pollen vectors. The female flowers also emitted indole, a known fly attractant. It is therefore likely that Tasmannia lanceolata is dependent on the services of diverse insects, especially Diptera, for promoting fruit set. Plantations should be established in the vicinity of biodiverse native vegetation that supports a wide variety of native flying insects capable of transferring pollen. 相似文献
999.
Anne B. Alerding Matthew R. Waalkes Emily S. Hill Richard A. Rowe Garrett Parsons 《Journal of Crop Improvement》2018,32(2):156-174
In soybean (Glycine max (L.) Merr.), stems remain a competitive carbon resource sink during reproduction. Radial stem expansion after termination of axial stem growth requires resources to produce secondary cell walls in secondary vascular tissues. The impact of both the timing and extent of secondary growth in stems on fruit production in soybean is unknown. We hypothesized that cultivars gaining higher amounts of secondary vascular tissues during seed filling would experience lower reproductive output. Four determinate cultivars were grown in a greenhouse and harvested at the beginning and ending of seed filling for biomass determination and tissue composition measurement (ImageJ-Fiji). Cultivar ‘Hanover’ entered seed filling with the lowest amount of secondary phloem. It produced the largest increase in radial stem expansion, largest seeds, and fewest undeveloped (aborted) fruits. The physiological role of active secondary phloem production in stems for seed production in soybean reproduction is unclear. We reject our initial hypothesis and propose that high fitness may require the concomitant growth of vegetative and reproductive organs. 相似文献
1000.
为探究黄土高原旱塬区不同覆盖模式对冬小麦耗水及根系生长的影响,采用微根管动态监测技术,连续两年对比分析平作不覆盖(T0)、秸秆覆盖平作(T1)、半膜覆盖垄作(T2)和垄上覆膜沟覆秸秆(T3)4种处理下冬小麦不同生育时期0~130 cm土层根系密度及土壤水分的变化。结果表明,与T0处理相比,T1、T2和T3处理对冬小麦耗水总量无显著影响,T1、T2和T3处理的水分利用效率分别提高25.42%、 9.68%和 20.13%。T1、T2和T3处理均会减小冬小麦根系富集深度,使根系分布深度上移,根系富集区离地表深度表现为T2相似文献