温度对波纹龙虾消化酶活力的影响

研究了波纹龙虾温度对不同消化器官中消化酶活力的影响,为人工饲料科学配制依据。用酶学分析方法,设计6个温度梯度(20℃、25℃、30℃、35℃、40℃和45℃),分别测定波纹龙虾胃、肠和肝胰脏的类胃蛋白酶、胰蛋白酶、淀粉酶和脂肪酶的活力。结果显示:在反应温度20℃~45℃范围内,波纹龙虾胃、肠、肝胰脏内的消化酶均随着温度的升高表现为先升后降趋势;不同消化器官中胃蛋白酶活力值出现拐点的温度不一样,胃、肠和肝胰脏的胃蛋白酶活力最大的温度分别是30℃、35℃和40℃;不同消化器官胃蛋白酶的活力有显著差异(P0.05),大小依次为胃肠肝胰脏;波纹龙虾不同消化器官的类胰蛋白酶出现最大酶活力的温度相同,为40℃,但胃的类胰蛋白酶活力明显较肠和肝胰脏的低(P0.05),差值最大可达40 U/mg;波纹龙虾胃、肠和肝胰脏的淀粉酶活力在25℃均出现最大值;在消化器官中,肠道淀粉酶活力最大,与胃和肝胰脏的酶活力有显著性差异(P0.05);波纹龙虾胃、肠和肝胰脏内的脂肪酶活力最大的温度为30℃,活力最高的是肝胰脏,胃内的脂肪酶活力明显的比肠和肝胰脏的要低(P0.05)。     

胡椒园间作槟榔体系小气候对胡椒产量的影响

为确定胡椒园间作槟榔体系影响胡椒产量的关键小气候因子,在海南胡椒园间作槟榔优势区开展4种间作模式与单作胡椒园小气候因子对产量影响的为期4 a的试验,研究不同间作密度下,对胡椒产量有主要贡献的灌浆期的叶片光合作用参数、每日最高和最低气温、不同深度土层土壤温度和含水量,分析胡椒园间作槟榔体系小气候因子对胡椒产量的影响。结果表明:合理间作可以提高胡椒产量,其中间作槟榔株数为765株/hm2的T2处理可以显著提高胡椒产量38.71%,为增产效应最大的处理。分析T2处理增产的原因,发现光强影响的关键光合参数气孔导度对产量有极显著正效应,光合有效辐射、光合速率对产量有显著正效应,T2处理显著提高了这三个光合参数;高温干旱的灌浆期胡椒园日最高温和升温幅度与产量负相关,T2处理显著降低了这两个参数,使胡椒产量增加;表层土壤温度与产量呈负相关关系,T2处理显著降低了表层土壤温度,对胡椒根系有保护作用。综合分析,发现光合有效辐射、日最高温、升温幅度和表层土壤温度是影响胡椒产量的关键小气候因子,所以,这几种小气候因子是用来确定间作模式是否合理的关键参数。     

Effect of steam explosion on enzymatic hydrolysis and baking quality of wheat bran

In this study, the effect of steam explosion (SE) treatment on microstructure, enzymatic hydrolysis and baking quality of wheat bran was investigated. Coarse and fine bran were treated at different steam temperatures (120–160 °C) and residence times (5 or 10 min) and then hydrolysed with carbohydrase enzymes. The SE treatment increased water extractable arabinoxylan (WEAX) content from 0.75 to 2.06% and reducing sugars from 0.92 to 2.41% for fine bran. The effect was more pronounced with increased SE temperature and residence time. The highest carbohydrate solubilisation was observed in fine bran at SE treatment of 160 °C, 5 min. WEAX content increased to 3.13% when this bran was incubated without enzyme, while WEAX content increased to 9.14% with enzyme addition. Microscopic analysis indicated that cell wall structure of wheat bran was disrupted by severe SE conditions. Supplementation of SE treated (150 °C, 10 min) bran at 20% replacement level decreased the baking quality of bread. However SE followed by enzymatic hydrolysis increased specific volume and decreased crumb hardness (on the day of baking and after three days of storage). Phytic acid content of bread supplemented with SE treated bran was lower than the one supplemented with untreated bran.     

A novel combined recirculating treatment system for intensive marine aquaculture

This study established a pilot‐scale recirculating treatment system that coupled an ecological process with a biological process to achieve adequate water quality and to minimize the water consumption for intensive marine culture. The recirculating treatment system consisted of a settling cell, a biofilter tank, a bivalve tank and gravel beds. The toxic pollutants, threatening the growth of bivalves, were reduced by the settling cell and the biofilter tank, so that the polyculture of shrimp and bivalves could be achieved. The living bivalve tank could function well as a remover of remaining small suspended solids (SS), and other pollutants. As the SS was reduced to a very low level by bivalve tank before the water flowing into the gravel beds, the risk of clogging was prevented. The studies suggested that the system maintained high removal efficiencies of SS, ammonium nitrogen () and nitrite nitrogen () and could contribute to the increase in shrimp yield.     

Interactions of baseflow habitat constraints: Macroinvertebrate drift,stream temperature,and physical habitat for anadromous salmon in the Calapooia River,Oregon

1. The Calapooia River in western Oregon supports a small winter steelhead trout (Oncorhynchus mykiss) population and historically supported spring Chinook salmon (Oncorhynchus tshawytscha). Early timber harvesting removed the riparian forest, and log transportation practices simplified the channel. Those disturbance legacies continue to affect fish habitat by limiting shade and channel complexity, complicating conservation efforts.
2. To evaluate juvenile salmonid rearing potential, macroinvertebrate drift, thermal regime and physical habitat were measured at eight sites in 24 km of the upper river during late summer baseflow.
3. Overall physical habitat was simple, with few functioning instream structures or pools. During the 22‐day drift study, flows declined and maximum site stream temperatures ranged from 23.1°C at the lower end to 16.4°C 24 km upstream.
4. Macroinvertebrate drift concentrations ranged from 0.7–13.7 ind. m^?3 with biomasses from 0.02–1.23 mg m^?3. Drift concentration biomass was higher upstream (P  = 0.006) than downstream and declined overall (P  < 0.001) during the study. Drift biomass was dominated by five taxon groups – Baetis tricaudatus, Calineuria californica, Hesperoperla pacifica, Simulium spp., and Chironomidae, which were 65% of total biomass. During twilight, total biomass and biomass of B. tricaudatus, Simulium spp., and Chironomidae (both larvae and adults) were higher.
5. Total drift declined dramatically over the study period owing to decreases in drift concentration and a 58% decline in discharge, greatly reducing overall drift and available food resources for juvenile‐rearing salmonids.
6. The upper catchment, both with cooler temperatures and higher food availability, provided the best conditions for juvenile anadromous salmonids to survive late summer conditions. Conservation consequences of climate change‐induced alterations in flow and temperature may further affect habitat quality for juvenile salmonids in this catchment in the coming decades.

     

An investigation on the effect of heat-moisture treatment on baking quality of wheat by using response surface methodology

Effect of heat-moisture treatment on quality properties of two bread wheats (cvs. Tosunbey and Bayraktar) were investigated by using response surface methodology (RSM). Temperature and moisture conditions in the experimental design were in the range of 55–95 °C and 13–19%. Heat-moisture treated grains were milled into flour and quality properties were determined. The optimum moisture-temperature combination for the highest dry gluten, Zeleny sedimentation, Alveograph W and bread volume values were estimated as 14%-63 °C for Tosunbey and 19%-55 °C for Bayraktar samples. Alveograph W seems to be a good indicator of baking quality for wheats treated at higher temperatures. In order to describe the relationship between the dependent and independent variables (moisture, temperature), the response values were fitted by second order polynomial models. Significance analysis showed that the effect of both moisture and temperature on dry gluten content, sedimentation and falling number values for Tosunbey; falling number and damaged starch values for Bayraktar were significant (p < 0.05). The effect of temperature on Farinograph water absorption, W and P/G, bread volume and firmness values were significant for both cultivars (p < 0.05). It can be concluded that improvement in baking quality can be achieved and flours with different properties can be produced by heat-moisture treatments on wheat.     

Settlement behavior of American lobster (Homarus americanus): effect of female origin and developmental temperature

The benthic settlement success of American lobster (Homarus americanus) postlarvae is a key factor in population dynamics, with the temperature being a key factor. Given the spatial distribution of the species, its pelagic larvae probably encounter various thermal zones during development. Little information is available on the ability of lobster larvae to acclimate to temperature or if this ability varies among geographic areas. The main objectives of this study were to characterize (i) the settlement behavior of the postlarvae in relation to (a) temperature during larval development and (b) the geographic origin of the maternal parent and (ii) the behavioral response of postlarvae with different thermal histories in the presence/absence of a thermocline. Results did not support the hypothesis of thermal adaptation among local populations, as settlement behavior of postlarvae did not differ among females from different geographic regions. In contrast, larval survival and settlement behavior and postlarval energetic conditions varied with development temperature. Behavioral plasticity in the benthic settlement was observed in relation to temperature structure of the experimental water column. This study suggests that there may be links between development temperature and the natural variability in survival and settlement of American lobsters. Findings emphasize the need for an integrated approach in lobster recruitment studies with the inclusion of behavior in dispersion models.     

小型低维护景观设计探析

通过对国内外低维护景观的实践案例分析,认为植物景观因其独特的美学和生态价值已然成为生活中不可或缺的一部分。探讨了低维护景观的概念,以及小型低维护景观设计的必要性、可行性和发展前景。将景观维护成本的影响因素归结为植物更替、设备维护,进而从低维护植物设计和种植容器设计两方面探讨了小型景观维护成本的控制问题。通过构建从雨水收集到自动循环利用的系统,根据植物生长特点,合理搭配种植,建立一个美观实用的小型低维护景观。     

海南水稻生育期的时空变化特征及对气候变暖的响应

基于海南6个农业气象观测站点的水稻生育期资料和1961~2014年历史气象数据,分析了海南不同地区水稻生育期的时空分布特征,以及气候变暖对海南水稻生育期的影响。结果表明,近54 a海南水稻生长季内平均气温呈上升趋势,早稻气候倾向率为0.21~0.3℃/10 a,以苗期最为明显,晚稻为0.18~0.24℃/10 a,以成熟期最为明显。不同地区水稻生育期差异较大,东部地区早于西部地区,早稻播种时间最大相差55 d,早稻收获和晚稻播种最大间隔42 d,降水和高温可能是造成这一差异的主要原因。随着气候变暖,海南大部分地区早稻生育期提前,晚稻生育期延迟,苗期和成熟期持续时间缩短,与该阶段平均气温呈负相关,但全生育期持续时间变异较大,部分站点略有延长。在未来气候变暖背景下,海南早稻播期可适当提前,晚稻播期可适当延迟,并选用耐高温和抗干旱品种,以减轻高温的不利影响。