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1.
单宁酶的固定化及其在酯型儿茶素水解反应中的应用   总被引:18,自引:0,他引:18  
采用自制的壳聚糖为载体对单宁酶(TA)固定化,TA与壳聚糖配比1:2.5,30℃固定2h,活力回收达23.6% ̄33.1%;偶联效率为84.9% ̄88.0%。固定化单宁酶(ITA)的表观Km值(以没食子酸丙酯为底物)为22.2×10^-6mol/L,TA的Km值(以没食子酸丙酯为底物)为10×10^-6mol/L,TA和ITA的最适反应温度分别为40℃和50℃;60℃处理15min,残存活性分别为  相似文献   

2.
孙善澄  袁文业 《遗传学报》1996,23(3):214-219
通过胚培养产生了小麦-偃麦草-簇毛麦-黑麦四属杂种。用4个六倍体小偃麦,2个六倍体小簇麦,2个六倍体小黑麦及1个八倍体小偃麦配置了6个四属杂种组合。结果没有出现高度不亲和性。6个组合的杂交结实率分别为6.2%、9.4%、2.4%、9.5%、25.0%和3.9%;胚培成苗率分别为12.1%、20%、37.4%、40%、1.1%和7.1%。结果表明,杂交结实率与胚培成苗率间没有相关性。杂种F1生活力旺盛,形态具有四个属的特征特性。杂种属于自交高不育与低育类型。5个低育类型自交结实率平均约1.2%。四属杂种体细胞染色体数目的变化为36、37、38、39、40和41。其中多数属于具有38个左右染色体的植株。  相似文献   

3.
采用自制的壳聚糖为载体对单宁酶(TA)固定化,TA与壳聚糖配比1:2.5,30℃固定2h,活力回收达23.6%~33.1%;偶联效率为84.9%~88.0%。固定化单宁酶(ITA)的表观Km值(以没食子酸丙酯为底物)为22.2×10-6mol/L,TA的Km值(以没食子酸丙酯为底物)为10×10-6mol/L,TA和ITA的最适反应温度分别为40℃和50℃;60℃处理15min,残存活性分别为13.6%和60.3%。TA和ITA的最适pH值分别为5.8和6.4;TA在pH4.8~7.8活力稳定,而ITA活力稳定范围在pH4.8~6.8.ITA作用于EGCG的半衰期为78.7h,EGCG水解率达90.3%。对茶多酚提取物进行水解,其所含的酯型儿茶素EGCG和ECG水解率分别为96.4%和96.8%,非酯型儿茶素EGC和EC的含量显著增加。  相似文献   

4.
棉田生态系统氮营养元素循环的研究   总被引:9,自引:0,他引:9  
陈金湘  刘海荷 《生态学报》1998,18(4):348-352
在棉田生态系统N循环中,低,中,高,超高产棉田N素的输入与输出不平衡,亏盈值(Bk)分别为-9.8,-10.6,-13.5和-16.2kg/hm^2,平衡值(B1)为0.9113,0.9435,0.9429.0.9458,每种1季棉花,土壤库现存N减少2‰~6‰,低,中,高,超高产棉田产物N输出,分别为棉田生态系统总输出N的54.4%,46.5%,44.9%和43.4%,其中经济产品(棉子和纤维)  相似文献   

5.
梯度磁场对冬小麦种子萌发影响的研究   总被引:8,自引:0,他引:8  
用梯度磁场处理 B73、3338、品 9 和二粒燕冬小麦种子,结果表明,各品种处理 4 分钟时,品 9、二粒燕的发芽势比对照平均高 102% 、97% 和 56% 、58% ;而 B73、3338 则比对照平均低 62% 、58% 和121% 、145% 。同时发现,对同一品种处理不同时间时,其发芽势和发芽率不同,对3338 而言,处理 2 分钟比处理 1 分钟和8 分钟高,对于品 9 则处理4 分钟比处理 1 分钟和 2 分钟高。结果还表明,处理 1、2、4 分钟的各品种种子浸泡液的电导率比对照都高,而处理 8 分钟,各品种的电导率稍低于或接近对照  相似文献   

6.
我们采用本院基础医学研究所组建的IL-6工程菌E.coilDH5a(pBV-hlL-6),在选定的培养基及pH值下,采用30升发酵罐进一步观察了工程菌的生长和rIL-6的表达,确定了发酵工艺条件。在此条件下连续进行了三批次的培养试验。结果表明,工程首的生长密度达到2.51±0.02g[干重]/L[发酵液],rIL-6产率为182.4±2.0mg/g[干重]。rIL-6以包涵体形式表达于大肠杆菌细胞中,破菌后选用非离子型去垢剂或尿素等变性剂提取包涵体中的杂蛋白,可使rIL-6的纯度达到70.1±1.3%,收率为71.9±1.9%。洗涤后的包涵体,经过凝胶柱纯化和复性,rIL-6纯度达到95%以上,柱纯化的收率为72.3±0.9%;采用依赖IL-6,小鼠杂交瘤细胞系7TD1及MTT比色法测定生物活性,rIL-6比活性达2×108U/mg。  相似文献   

7.
牟秀林 《生态学报》1994,14(3):318-322
辽东半岛水利建设造成洄游型香鱼资源下降,并在碧流河水库、转角楼水库形成了陆封型香鱼。陆封型香鱼发生了①个体小型化:体长和体重由洄游型香鱼的20─25cm(平均22.6cm),150─250g(平均204g),分别下降到10─18cm(平均13.6cm),和13─73g(平均36.5g)。②性状变异:洄游型香鱼体长为体高的3.7─4.7倍,为头长的4.5─5.3倍,而陆封型香鱼体长为体高的4.3─6.5倍,为头长的3.9─4.3倍。③怀卵量减少,产卵期提前:洄游型香鱼怀卵量为1.0─8.5万粒(平均3.1万位).产卵盛期为9月底至10月上旬,而陆封型香鱼的怀卵量为0.32─0.61万粒(平均0.40万粒),产卵盛期为9月上旬至下旬,提前20d左右。  相似文献   

8.
几个水稻品种抽穗期主效基因与微效基因的定位研究   总被引:18,自引:1,他引:17  
林鸿宣  钱惠荣 《遗传学报》1996,23(3):205-213
在构建2张RFLP图谱的基础上,定位分析了控制水稻抽穗期的主效基因和微效基因。在特三矮2号/C.B.群体中定位到2个主效基因和2个微效基因。该2个主基因分别位于第3、8染色体上,累加贡献率约达50%,加性效应值分别为7天和6天,而分别位于第1、12染色体的2个微效基因的贡献率仅分别为8.3%和9.6%,加性效应值仅为3天和4天。在外引2号/C.B.群体中定位了2个连锁于第6染色体的主效基因和1个位于第8染色体的微效基因,该2个主效基因的贡献率分别为35.5%和27.4%,来自外引2号的该2个基因其效应均为明显推迟抽穗,因而可推测它们为感光性基因,微效基因的贡献率仅为8.9%,基因效应值较小。  相似文献   

9.
保安湖沙塘鳢的食性、繁殖、年龄及生长的研究   总被引:22,自引:0,他引:22  
保安湖沙塘鳢1冬龄成熟,雌雄比1:1.34,4月初至6月中旬繁殖;个体绝对繁殖力540—1943egg(1154±314egg)。渔获物中以体长8.0—14.0cm,体重10.0—40.0g,2、3龄个体为主。体长-体重关系为W=0.02129L3.0585。3龄前生长较快;雄鱼略快于雌鱼。肥满度冬春季较高,最高在3月。体长和体重与年龄的关系可用Bertalanffy生长方程描述,参数分别为:雌鱼L∞=15.29cm,k=0.4072,t0=0.1596,W∞=84.9g;雄鱼L∞=16.71cm,k=0.3736,t0=0.1095,W∞=118.5g;体重生长拐点年龄和拐点体重雌鱼分别为2.86a和25.1g,雄鱼3.13a和35.4g。  相似文献   

10.
发头裸腹SouMoinairrasaBrehm(Cladocera)在25±1℃下有3个幼龄,6个成龄,平均寿命为167.7h,平均最大体长为1.75mm平均产仔量为117个。rm为1.358/d;在30±1℃下有3个幼龄,7个成龄,平均寿命为121.0h平均最大体长为1.71mm,平均产仔量为106.6个,rm为1.650/d。在生命初期30±1℃下体重增长率(dW/dt),相对体长增长率(dL  相似文献   

11.
云南省纳帕海自然保护区越冬黑颈鹤的集群特征   总被引:3,自引:2,他引:1  
2004年10月-2005年5月,在云南纳帕海自然保护区采用定点扫描法对越冬黑颈鹤(Grus nigricollis)的集群类犁和集群大小进行了观察.结果表明黑颈鹤夜间集群夜栖,形成较大的夜栖群,平均群体大小为67.9只(16-157,n=17):按照有无灰鹤加入,又将其分为同种集群和混种集群两种类型,其中同种集群的黑颈鹤数量占整个越冬种群的65.3%.在白昼,黑颈鹤以家庭鹤、集群鹤及特殊群体3种类型活动,家庭鹤和集群鹤的平均大小分别为2.7只(2-4,n=145)和16.1只(3-65,n=1017).黑颈鹤的集群大小并不稳定,在日内和月份间均有明显变化(P=0.000<0.05).存越冬期,最大集群形成于12月,其次为11月和1月;在日内,早上8时集群最大,随后减小并保持相对稳定,18时黑颈鹤开始向夜栖地靠拢,使得集群再次开始增大.随后观察中还发现,黑颈鹤的家庭解体过程开始于3月底,当幼鹤被成鹤驱逐离群后,逐渐加入集群鹤活动,从而使得家庭鹤和集群鹤的大小和组成发生改变.黑颈鹤的集群大小和组成受自身状况、种内关系、天气、食物等多种因素的共同影响,随时间和季节变动而发生变化,是对自身、种群和环境条件变化的综合反映.  相似文献   

12.
散养与野生丹顶鹤孵卵期行为比较   总被引:3,自引:2,他引:1  
2007年4月在扎龙国家级自然保护区,采用瞬时扫描取样法对散养和野生丹顶鹤(Grus japonensis)的孵卵期行为进行了观察、比较.结果表明,散养丹顶鹤与野生丹顶鹤的孵卵期行为模式基本相同.在总体行为发生频次上,散养丹顶鹤的繁殖行为明显高于野生丹顶鹤,游走行为则低于野生丹顶鹤.行为日节律的比较表明,一天中散养丹顶鹤的繁殖行为波动小于野生丹顶鹤.由于人为干扰,散养丹顶鹤的繁殖行为显著高于野生丹顶鹤的繁殖行为(P<0.05).在个体间差异比较中,散养丹顶鹤与野生丹顶鹤在觅食表达上均存在显著差异(P<0.05),而散养丹顶鹤的警戒行为表达也存在显著差异(P<0.05).  相似文献   

13.
The baculum in Arctocephalus p. pusillus reaches up to 14.1 cm in length, 13.5 g in mass, and 1.3 g/cm in density (= mass/length). A pubertal growth spurt occurs between 2 and 3 yr of age, when bacular length increases by 28%, mass by 124%, and density by 77%; concurrently, body length increases by 14%. A second, weaker spurt occurs at social maturity (9-10 yr of age). Testes grow most rapidly between 1 and 2 yr of age, when testicular length increases by 29%. After 3 yr of age, growth in bacular and testicular length slows, and bacular mass continues to increase approximately linearly. Bacular and testicular lengths average 6.8% and 3.4% (respectively) of body length in adults, compared with 9.9% and 5.7% in the promiscuous harp seal ( Pagophilus groenlandicus ). Bacular length, mass, and density, and testicular length, are positively allometric to body length over growth; bacular length is isometric to testicular length. Among animals of the same age, bacular length and mass are positively allometric to body length in young animals, with negative allometry or isometry thereafter; testicular length is isometric to body length in young animals and negatively allometric thereafter. Patterns of early growth and allometry of the baculum and testes are interpreted as adaptations for mating opportunities, years before territoriality is possible. The baculum and testes of adult Cape fur seals and other otariids are small compared with those of most phocids, because sperm competition among male otariids is weak.  相似文献   

14.
Potential factors influencing sperm survival under hypertonic conditions were evaluated in the Sandhill crane (Grus canadensis) and turkey (Meleagridis gallopavo). Sperm osmotolerance (300-3000 mOsm/kg) was evaluated after: (1) equilibration times of 2, 10, 45 and 60 min at 4 °C versus 21 °C; (2) pre-equilibrating with dimethylacetamide (DMA) or dimethylsulfoxide (Me2SO) at either 4 °C or 21 °C; and (3) inhibition of the Na+/K+ and the Na+/H+ antiporter membrane ionic pumps. Sperm viability was assessed using the eosin-nigrosin live/dead stain. Species-specific differences occurred in response to hypertonic conditions with crane sperm remaining viable under extreme hypertonicity (3000 mOsm/kg), whereas turkey sperm viability was compromised with only slightly hypertonic (500 mOsm/kg) conditions. The timing of spermolysis under hypertonic conditions was also species-specific, with a shorter interval for turkey (2 min) than crane (10 min) sperm. Turkey sperm osmotolerance was slightly improved by lowering the incubation temperature from 21 to 4 °C. Pre-equilibrating sperm with DMA reduced the incidence of hypertonic spermolysis only in the crane, at both room and refrigeration temperature. Inhibiting the Na+/K+ and the Na+/H+ antiporter membrane ion pumps did not impair resistance of crane and turkey spermatozoa to hypertonic stress; pump inhibition actually increased turkey sperm survival compared to control sperm. Results demonstrate marked species specificity in osmotolerance between crane and turkey sperm, as well as in the way temperature and time of exposure affect sperm survival under hypertonic conditions. Differences are independent of the role of osmotic pumps in these species.  相似文献   

15.
根据2009年7—8月、10月和2010年1月、5月黄海中南部渔业生物底拖网调查数据,对该海域细纹狮子鱼的生物学特征及其分布的季节变化作了分析。结果表明,细纹狮子鱼平均体长和平均体重从春季(4.7 cm、3.3 g)到冬季(34.2 cm、764.9 g)呈显著增加,并且雄性个体平均体长显著大于雌性个体(P<0.05,春季除外)。性比(♀∶♂)随体长组和季节变化,体长越大趋向于雄性,反之趋向于雌性;夏季雄鱼居多(0.70∶1,P<0.05),秋季则为雌鱼居多(1.35∶1,P<0.05),而冬季(产卵群体)和春季性比接近于1∶1。细纹狮子鱼各季节摄食等级均在2.5以上,冬季雄性个体摄食等级显著大于雌性个体(P<0.05),但雄性个体肥满度为全年最低(1.52)。细纹狮子鱼相对资源量和贡献率从春季(0.17 kg/h,1.54%)到秋季(15.36 kg/h,33.05%)呈上升状态,而冬季(2.37 kg/h,5.60%)有所下降。相比2000年,夏秋季相对渔获量和贡献率提高明显。全年集中分布于7.8—13.6℃,3.20%—3.38%的水域,平均体重和水深有显著的相关性(秋季除外)。另外,根据性成熟个体分布区和稚幼鱼分布的相关历史资料分析发现,除海州湾外,黄海中部深水区可能是细纹狮子鱼的产卵场。  相似文献   

16.
Bandeira  Salomão O. 《Plant Ecology》1997,130(2):133-141
Dynamic and structural aspects of Thalassodendron ciliatum were studied in the intertidal zones around Inhaca Island during the rainy seasons 1991 to 1993. Measurements comprised leaf growth rate, leaf detachment rate, biomass, above-ground to below-ground biomass ratios and total rhizome length. On average, three leaves were, at the same time, formed and detached from a shoot during 15 day periods and five leaves from a shoot during 30 day periods. Mean leaf growth rate varied from 101.2 to 159.5 mm, 313.2 to 366.9 mm and 540 to 583.0 mm for 15, 30 and 45 days of measurements respectively. Differences between locations (Banco Sidzanye, Barreira Vermelha and Portinho-EBM/BV) were not statistically significant for the 30 and the 45 day period, but significant for the 15-day period. The average leaf growth rate per day was between 14.1 to 18.3 mm day-1 shoot-1, and the average time for leaf turnover (6 to 9 leaves) on one shoot was four successive spring tides (around 45 days). The average above-ground to below-ground biomass ratio was 1: 1.5 (61% in below-ground biomass) and leaf biomass varied between 45.1 and 211.7 g DW m-2. Total rhizome length varied between 960.0 to 6641.6 cm m-2. A positive correlation was observed between this variable with rhizomes and roots and between rhizomes and roots.  相似文献   

17.
Smaller predator-prey body size ratios in longer food chains   总被引:2,自引:0,他引:2  
Maximum food-chain length has been correlated with resource availability, ecosystem size, environmental stability and colonization history. Some of these correlations may result from environmental effects on predator-prey body size ratios. We investigate relationships between maximum food-chain length, predator-prey mass ratios, primary production and environmental stability in marine food webs with a natural history of community assembly. Our analyses provide empirical evidence that smaller mean predator-prey body size ratios are characteristic of more stable environments and that food chains are longer when mean predator-prey body size ratios are small. We conclude that environmental effects on predator-prey body size ratios contribute to observed differences in maximum food-chain length.  相似文献   

18.
气候变化对鄱阳湖白鹤越冬种群数量变化的影响   总被引:2,自引:0,他引:2  
分析了1983—2011年鄱阳湖国家级自然保护区越冬白鹤种群数量的年际变化趋势,检验了白鹤种群动态与繁殖地和越冬地气候变化的相关性,气候变量包括月平均气温、月平均最高气温、月平均最低气温和月降水量。研究结果表明,鄱阳湖国家级自然保护区内的白鹤年最大数量平均为(2 130±153)只,呈显著地线性增长趋势(R2=0.454,F=22.441,df=28,P=0.000),但年际波动较大。在越冬地,越冬当年10月、11月、12月的气候变量与白鹤种群数量没有显著的相关性,但越冬初期10月份和越冬后期翌年3月份的气温变量与第4年、第5年、第6年及第7年的白鹤种群数量存在显著的正相关,表明越冬地气候对白鹤种群大小的影响存在时滞效应。越冬初期和末期可能是白鹤补充能量的关键阶段,而且越冬初期的气候可能也与冬季食物的数量或质量相关,因此这两个阶段的适宜气温可能有利于个体尤其是幼鹤的存活,使更多的个体参加繁殖,由于白鹤的性成熟年龄在3—5a,因此其对白鹤种群增长的有利影响会在3a以后表现出来。白鹤种群数量变化与繁殖地繁殖期的降水量没有显著的相关性,而与7月份的气温变量存在显著的正相关。多元线性回归分析结果表明,6a前的10月份平均最低温度、2a前的10月最高温度及5a前的10月平均气温是白鹤种群数量变化的显著预测因子,共同解释了鄱阳湖国家级自然保护区白鹤种群数量变化的74.8%(F=23.807,df=27,P=0.000)。  相似文献   

19.
To determine the beginning and end of the transition period from larvae to juveniles in anchoveta Engraulis ringens, seven morphometric measurements were carried out in 333 laboratory-reared and 324 field-caught larvae. Measurements of body morphometrics were employed to calculate the six body ratios selected to show transition changes described in this study. The analysis was carried out with 'dummy variables' (variables that take only one of two possible values: 0 or 1) because a single model was used to indicate the point at which the slope changes in piecewise linear regressions. The regression coefficients of the relationship between ratios of morphometric measurements and body length were not significant in any case (P > 0·05) and, accordingly, a discrete length at which the slope changes could not be estimated. The ratio of the measurements according to the age showed two inflections, corresponding to the beginning and end of the transition period. The first inflection occurred between 32 and 64 days (average 46 days); the second inflection occurred between 81 and 149 days (average 107 days). Therefore, the transition period lasted c. 61 days, starting with a high growth rate, continuing with a slower growth phase, and ending with the onset of a new high growth rate period that corresponded to the start of typical juvenile growth. On the basis of these results, it is hypothesized that the transition from larvae to juveniles in E. ringens is determined more by age than body size.  相似文献   

20.
Anthropogenic CO(2) emissions are acidifying the world's oceans. A growing body of evidence is showing that ocean acidification impacts growth and developmental rates of marine invertebrates. Here we test the impact of elevated seawater pCO(2) (129 Pa, 1271 μatm) on early development, larval metabolic and feeding rates in a marine model organism, the sea urchin Strongylocentrotus purpuratus. Growth and development was assessed by measuring total body length, body rod length, postoral rod length and posterolateral rod length. Comparing these parameters between treatments suggests that larvae suffer from a developmental delay (by ca. 8%) rather than from the previously postulated reductions in size at comparable developmental stages. Further, we found maximum increases in respiration rates of +100% under elevated pCO(2), while body length corrected feeding rates did not differ between larvae from both treatments. Calculating scope for growth illustrates that larvae raised under high pCO(2) spent an average of 39 to 45% of the available energy for somatic growth, while control larvae could allocate between 78 and 80% of the available energy into growth processes. Our results highlight the importance of defining a standard frame of reference when comparing a given parameter between treatments, as observed differences can be easily due to comparison of different larval ages with their specific set of biological characters.  相似文献   

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