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141.
研究了红树林的生态学特性和对城市发展的积极作用,对深圳市珠江三角洲地区红树林的生长区域现状进行了调查,红树植物适宜生长的环境对盐度、温度和潮间带有着特殊要求。探讨了结合当地经济产业和文化游憩活动,提出了采用基围养殖法和创造适宜微生长环境两种具体技术可持续地恢复红树林,并且与养殖业经济相辅相成。而对于该地块的总体规划策略要结合当地文化游憩活动,体现自然保护功能价值。  相似文献   
142.
土壤脲酶抑制剂正丁基硫代磷酰三胺的作用基团研究   总被引:6,自引:1,他引:5  
孙庆元  张雪崧  王艳红 《土壤》2007,39(3):492-495
土壤脲酶抑制剂正丁基硫代磷酰三胺(nBPT)是抑制土壤中尿素水解的最有效的化合物之一。分析大连工业大学合成的土壤脲酶抑制剂nBPT抑制脲酶活性的影响因素及作用机理,结果表明:在50°C,pH=5.91时,nBPT的抑制活性达到最大值;在nBPT各结构基团中,正丁基(-NH(CH2)3CH3)、硫基(-S)对nBPT与脲酶的结合起辅助作用,胺基(-NH2)是nBPT与脲酶结合的关键基团,与脲酶活性部位巯基(-SH)结合。土壤脲酶抑制剂nBPT与脲酶的具体结合机理还有待继续研究。  相似文献   
143.
为研究不同回收方法的肌浆蛋白对鲢鱼糜冻融稳定性的影响,分别通过加热法、酸偏移法和酸偏移-耦合壳聚糖絮凝法回收鲢鱼糜漂洗液中的肌浆蛋白,并将其添加至鱼糜中,测定鱼糜冻融循环过程中蛋白质冷冻变性、脂肪氧化及凝胶品质的指标。结果显示:添加不同方法回收的肌浆蛋白均能抑制鲢鱼糜冻融循环过程中盐溶性蛋白含量、Ca2+-ATPase活性和总巯基含量的下降以及表面疏水性的上升,其中加热法回收的肌浆蛋白抑制鱼糜蛋白质冷冻变性的效果最显著,经过9次冻融后仍能够对鱼糜蛋白质变性起到抑制效果。蛋白质羰基含量测定结果显示,肌浆蛋白的添加可以抑制鱼糜冻融循环过程中蛋白质氧化现象。而与空白组鱼糜相比,添加不同回收处理的肌浆蛋白的鱼糜,其硫代巴比妥酸值(TBARs)和pH值并没有显著变化。此外,随着冻融循环次数的增加,鱼糜凝胶品质会发生严重劣化,其中添加酸偏移-耦合壳聚糖絮凝处理的肌浆蛋白的鱼糜始终保持较好的凝胶质构性能。  相似文献   
144.
温度、盐度和光照对海蜇足囊繁殖的影响   总被引:7,自引:1,他引:7  
在实验室条件下,就温度、盐度和光照对海蜇(Rhopilemaesculentakishinouye)足囊形成和萌发的影响进行观察。温度实验在0~30℃范围内设7组,盐度实验在2~32.1‰范围内设16个梯度,光照分为自然光和黑暗两组。实验显示:10℃以上海蜇无足囊繁殖迹象,15~30℃范围内,随温度升高,海蜇足囊繁殖能力增强;6‰以下盐度,海蜇不能进行足囊繁殖,20~22‰是海蜇足囊繁殖的最适盐度;黑暗有利于足囊繁殖。温度是足囊繁殖的关键因子,盐度和光照是足囊繁殖的充分条件。作者认为,适宜的环境因子是海蜇螅状体形成的必要条件,尽管足囊可以抵御外界的恶劣环境,但足囊形成并非需要不良环境因子诱导,足囊繁殖是海蜇螅状体一种正常的无性繁殖方式  相似文献   
145.
ABSTRACT:    To evaluate the stocking effectiveness of the kuruma prawn Penaeus japonicus , a two-stage sampling survey of Gensiki bottom-drift-netters was carried out in Ariake Sound, Saga Prefecture, Japan. A total of 471 000 hatchery-produced juveniles, marked by cutting off the right uropods, was released. Thirty-three fishing days were randomly drawn from four boats, which were selected from the 80 boats operating in the fishery. All prawns caught on the selected days were examined, and the hatchery-produced individuals were identified by their regenerated uropods. A telephone survey of all boats was also conducted, to determine the number of fishing days. A total of 286 marked prawns were caught on the survey days for the Saga area in Ariake Sound, from the last half of July to the first half of September 2002. The recapture rate and standard error were estimated at 0.76 ± 0.52%. Economic efficiency was estimated at 0.28 ± 0.02. Strategies for sampling schemes and stock recovery are also discussed.  相似文献   
146.
温度和盐度对花鲈胚胎及前期仔鱼发育影响的初步报告   总被引:30,自引:0,他引:30  
花鲈(Lateolabrax japonicus)胚胎发育的适宜温度为10~22℃,10℃组中的畸形率偏高,因此最适宜温度为13~22℃。短时期的7℃低温对胚胎发育没有影响;前期仔鱼的适温范围与胚胎的适温范围基本一致。胚胎发育的适宜 盐度为19‰~28‰,以22‰~25‰为最佳;仔鱼对盐度的要求与胚胎期近似。以低盐度和高盐 度相比较,4日龄以后,低盐度似有利于仔鱼存活。  相似文献   
147.
温度、盐度对大银鱼胚胎发育的影响   总被引:6,自引:0,他引:6  
大银鱼胚胎发育的温度、盐度生态幅较宽,适温范围为0.9~1.52℃.孵化过程中昼夜温差不宜超出1~3℃。胚胎发育的盐度上限为18%,仔鱼在4.3%以下可正常生活。  相似文献   
148.
Background: The minimum set of sub-models for simulating stand dynamics on an individual-tree basis consists of tree-level models for diameter increment and survival. Ingrowth model is a necessary third component in uneven-aged management. The development of this type of model set needs data from permanent plots, in which all trees have been numbered and measured at regular intervals for diameter and survival. New trees passing the ingrowth limit should also be numbered and measured. Unfortunately, few datasets meet all these requirements. The trees may not have numbers or the length of the measurement interval varies. Ingrowth trees may not have been measured, or the number tags may have disappeared causing errors in tree identification. Methods: This article discussed and demonstrated the use of an optimization-based approach to individual-tree growth modelling, which makes it possible to utilize data sets having one or several of the above deficiencies. The idea is to estimate all parameters of the sub-models of a growth simulator simultaneously in such a way that, when simulation begins from the diameter distribution at the first measurement occasion, it yields a similar ending diameter distribution as measured in the second measurement occasion. The method was applied to Pinus patula permanent sample plot data from Kenya. In this dataset, trees were correctly numbered and identified but measurement interval varied from 1 to 13 years. Two simple regression approaches were used and compared to the optimization-based model recovery approach. Results: The optimization-based approach resulted in far more accurate simulations of stand basal area and number of surviving trees than the equations fitted through regression analysis. Conclusions: The optimization-based modelling approach can be recommended for growth modelling when the modelling data have been collected at irregular measurement intervals.  相似文献   
149.
Background: Progress of forest production in response to the environment requires a quantitative understanding of leaf area development. Therefore, it is necessary to investigate the dynamics of seasonal crown foliage in order to understand the productivity of mangroves, which play an important role in the subtropical and tropical coastlines of the world. Method: Crown foliage dynamics of the mangrove Rhizophora styloso were studies to reveal patterns of leaf recruitment, survival and seasonal leaf area growth. Results: Flushing of leaves occurred throughout the year, but both flushing and leaf area growth pattern of leaves varied with season. Maximum flushing occurred in summer, but leaf areas did not differ significantly with season. The half-expansion period is longer, and the intrinsic rate of increase was lower in winter. Summer flushed leaves grew faster at their initial stage and reached their maximum area over a shorter period of time. The difference in temperature and air vapor pressure deficit (VPD) between summer and winter contributed to the present dynamics of foliage patterns. The mean leaf longevity was estimated to be 13.1 month. The crown foliage area was almost stable throughout the year. Conclusions: Homeostatic control of the crown foliage area may be accompanied by the existence of ecophysiological mechanisms in R. stylosa. Integrating crown foliage dynamics into forest models represents an important step towards incorporating physiological mechanisms into the models for predicting growth responses to environmental changes and for understanding the complex responses of tree growth and litter production.  相似文献   
150.
指出了高速公路的建设对环境具有较强的破坏作用,不仅影响景观,还影响植被的生长。为了能尽快恢复植被的生长,对高速公路边坡生态恢复中先锋树种的选择进行了研究。阐述了边坡绿化的功能,提出了高速公路边坡先锋植物的选择原则和习性要求,分析了垄茶高速公路边坡的环境特点,并探讨了其边坡绿化的有效措施,特别是就先锋树种选择、植物的文化内涵和植物配置等方面进行了研究。提出了应用植物35种,其中包括豆科、蔷薇科、杜鹃花科、胡颓子科、桦木科、鼠李科等。其结果对国内高速公路边坡植被恢复具有较强的参考价值。  相似文献   
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