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151.
为研究木瓜蛋白酶酶解鱿鱼皮的最佳酶解条件,通过单因素试验研究了酶添加量、酶解时间和酶解温度对鱿鱼皮水解度的影响。结果显示,3个因素对鱿鱼皮水解度均有不同程度的影响。在单因素试验的基础上,以水解度为响应值,酶添加量、酶解时间和酶解温度为自变量,采用Box-Benhnken响应面法设计3因素3水平优化试验,通过响应面分析,建立了二次多项数学模型对酶解条件进行优化,获得木瓜蛋白酶酶解鱿鱼皮的最佳条件:酶添加量4 560 U/g,酶解时间3.2 h和酶解温度50℃。在该条件下木瓜蛋白酶酶解鱿鱼皮的水解度可达15.53%,与模型预测值基本一致。研究表明,通过响应面法获得的数学预测模型能较好地预测木瓜蛋白酶酶解鱿鱼皮的效果,试验结果为鱿鱼加工副产物高值化利用提供了参考。  相似文献   
152.
通过模拟氮沉降试验(设置2种氮形态5种施氮水平(N0、N1、N2、N3、N4分别代表0、20、40、60、80 kg·hm-2·a-1,共10个处理)研究杉木林土壤微生物区系的变化。结果表明:沉降第1年,高氮处理对微生物数量的影响较显著,氮处理时微生物数量的变化波动较大;沉降1年后,各处理的变化规律稳定,波动较小。12月份各处理间微生物数量和细菌数量变化幅度较小、氮处理对其影响不显著,故不宜在12月采集土样。氮沉降量影响微生物总量,总体而言低氮处理促进微生物生长,最高氮处理抑制微生物生长,NH4+-N2或N3和NO3--N3处理微生物总量最多。不同微生物类群对氮沉降形态和沉降量的响应不同,土壤细菌的变化规律和微生物数量的变化规律一致,低氮处理时,硝态氮处理对细菌数量生长的影响大于铵态氮处理,2种形态氮的N2或N3处理细菌数量最大。铵态氮比硝态氮更易影响真菌的生长,且NH4+-N1和NO3--N3处理真菌数量最多。不同氮沉降形态对放线菌数量影响显著,沉降1年后高氮沉降量对放线菌生长略有促进作用。  相似文献   
153.
在实验室条件下,以玉米禾螟卵和麦蛾卵为寄主,观察了禾螟赤眼蜂的功能反应。初步结果表明,在寄主卵密度为5,10,20,40粒的条件下,赤眼蜂对寄主的寄生率随卵的密度增加而增加,但密度由40粒增加到80粒时,寄生率的变化较为平缓。每只雌蜂寄生的卵粒数随着赤眼蜂密度的增加而减少。寄主密度的变化对赤眼蜂子一代的雌蜂比率无明显影响。  相似文献   
154.
不同 LED 光源对乌塌菜光合特性及品质的影响   总被引:1,自引:0,他引:1  
以菊花小八叶乌塌菜品种为试验材料,利用LED精量调制光源,设红光、蓝光、红/蓝(3/1)、红/蓝(7/1)、白/红/蓝(3/2/1)5个处理,以白光为对照,研究不同光质对乌塌菜光合特性及品质的影响。结果表明:叶绿素含量以红/蓝(7/1)处理最高,且叶绿素总量与红/蓝光比值呈正相关;光合速率、气孔导度、蒸腾速率均以红光处理最高,而蓝光处理下有较高的胞间CO2浓度;不同光质处理对乌塌菜的荧光参数有较大影响,白光的Fm/Fo、Fv/Fo和ΦPSⅡ均最大;红光可以提高可溶性糖含量而蓝光却能提高可溶性蛋白含量,白光能增加维生素C含量。综合分析得出,红/蓝(7/1)有利于增加光合色素含量,提高光合速率和营养品质。  相似文献   
155.
Oxidative stress-induced neuronal cell loss is considered to be the major mechanism underlying the pathogenesis of neurodegenerative diseases, which could be induced by a high concentration of glutamate. In this study, sargachromenol (SC) was isolated from a marine brown seaweed Sargassum horneri (S. horneri) and its neuroprotective effects against glutamate-induced oxidative stress in HT22 cells were investigated. An MTT assay was applied to assess the cytotoxicity of the SC, and the efficacies of SC were determined by flow cytometry, an analysis of ROS production, quantitative Real-Time PCR, and the Western blot assay. Our results showed that the pretreatment of SC reduced glutamate-induced apoptosis in HT22 cells via inhibiting the sub-G1 population, DNA fragmentation, and nuclear condensation, as well as up-regulating anti-apoptotic protein (Bcl-2) and down-regulating apoptotic proteins (Bax, p53, cleaved-PARP, caspase-3, caspase-9, and cytochrome c). Additionally, SC attenuated glutamate-induced oxidative stress by suppressing mitogen-activated protein kinases (MAPKs;ERK, JNK, and p38) and nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) signaling (IκBα and NF-κB p65), while activating nuclear factor erythroid-2-related factor 2 (Nrf2)/heme oxygenase 1 (HO-1) signaling (Nrf2; HO-1, and NQO-1). Our results suggest that SC could be used as a pharmacological candidate for the prevention and treatment of neurodegenerative diseases.  相似文献   
156.
针对绿豆收获清选过程中清选损失率高、籽粒含杂率高的问题,研发了一种双斜面风筛式绿豆清选装置。运用流固耦合仿真模拟绿豆清选过程,并开展了正交试验。同时运用二次回归方程分析和响应面分析等方法对相关试验因素对籽粒含杂率、清选损失率的影响进行了探究。进行了最优组合参数验证试验,试验结果表明,该参数组合符合性能指标要求,实物模型可用于后期田间试验。  相似文献   
157.
一品红不同品种叶片叶绿素荧光特性比较   总被引:6,自引:1,他引:6  
李畅  苏家乐  刘晓青  李倩中  陈璐  陈尚平 《园艺学报》2009,36(10):1519-1524
 利用叶绿素荧光技术测定了一品红4个品种‘金多利’、‘圣诞天使’、‘索诺拉飞雪’、‘旗帜’叶片光强依赖的叶绿素荧光特性。结果表明: ‘金多利’初始荧光( Fo ) 、最大荧光( Fm ) 和可变荧光( Fv ) 值极显著高于其它3个品种。在各个光强( PAR, 0~2 171μmol·m- 2 ·s- 1 ) 下, 表观电子传递速率( rETR) 、实际光化学效率(Yield) 和光化学淬灭( qP ) 的变化趋势一致, 均为‘金多利’ > ‘圣诞天使’ > ‘索诺拉飞雪’ > ‘旗帜’, 在高PAR下这种差异更明显。拟合参数最大潜在相对电子传递速率( rETRmax ) 、半饱和光强( Ik) 和光抑制参数(β) 也同rETR等具有一致变化。说明‘金多利’有较高的PSⅡ活性, 耐强光; 而‘旗帜’则光化学效率较弱, 高光强下易受光抑制。  相似文献   
158.
We reported that meat chicks have either a greater capability to acclimatize to novel environments, or a blunted hypothalamic‐pituitary‐adrenal response to novel environments compared with layer chicks in a commercial base. The present study compared the differences in behavior and plasma corticosterone concentrations under isolation‐induced stress between neonatal meat and layer Nagoya chicks which had been separated from the same population. Both types of neonatal chicks reared in groups were individually separated and their spontaneous activity and distress‐induced vocalizations were monitored for 10 min. The responses of the two types were remarkably different, with the meat chicks being less active than the layer chicks. Distress‐induced vocalizations were fewer in the meat than in the layer chicks. The meat chicks spent more time in a sleeping posture during isolation‐induced stress. Plasma corticosterone concentrations measured at the end of the test tended to be higher in the layer chicks than in meat ones, but not significantly. In conclusion, the selection of Nagoya chickens for meat and layer may have trends similar to those observed in commercial chickens in relation to stress susceptibility.  相似文献   
159.
Late blight (LB), caused by Phytophthora infestans, is a destructive disease of tomato (Solanum lycopersicum) worldwide. Currently, there are few commercial cultivars of tomato with resistance to LB, and the disease is mainly controlled by heavy use of fungicides. Due to the emergence of fungicide‐resistant pathogen isolates, there is a concerted effort to identify new genetic sources of resistance and breed new resistant cultivars. A recent screening identified several new tomato accessions with strong resistance to LB. Here, we report on the genetic basis of LB resistance in S. pimpinellifolium accession PI 270441, as determined by generation means analysis and analysis of response to selection, using populations derived from crosses with LB‐susceptible breeding line Fla. 8059. Heritability of LB resistance ranged from 0.76 to 0.78, and the minimum number of genes was estimated 1—few. These results suggest that transfer of LB resistance from PI 270441 to the cultivated tomato should be feasible via a traditional backcross breeding approach. Genetic mapping studies are underway to identify molecular markers associated with resistance in this accession.  相似文献   
160.
Phenotypic (rp), genotypic (rg), genotype × location (rgl) and error (re)correlations for important agronomic characters were estimated for eleven Norwegian populations of white clover (Trifolium repens L.), originating from between 58°52′N and 69°30′N latitude, and from altitudes of 10 to 450 m a.s.l. The populations were evaluated in monoculture clonal field plots for two years at two locations in Norway. All pairwise correlations between foliage height, leaflet length, dry matter yield (DMY) and general performance were positive and significant. Winter survival was positively correlated with general performance, spring growth and DMY, but negatively associated with internode length, while seed yield showed a small positive genotypic correlation with foliage height. Considerable differences were, however, revealed among populations with regard to sign and magnitude of the estimated correlations. Within-population estimates of rg were consistently positive between DMY, general performance and most other characters; between foliage height on the one hand and leaflet length, winter survival and seed yield on the other hand, and between internode length and leaflet length, indicating pleiotropy. Correlations involving other character-combinations varied substantially among populations, and imply presence of linkage and/or coadaptation. Path coefficient analysis was used to partition the genotypic correlations between some of the characters into direct and indirect effects. Path coefficients revealed that foliage height had the highest positive direct effect on DMY, followed by winter survival and internode length. Leaflet length, which showed a positive, significant simple correlation with DMY, exhibited a negligible direct influence, counterbalanced nearly completely by the positive indirect effect on DMY via foliage height. Positive indirect effects on DMY via foliage height were also found for winter survival and internode length. The coastal populations from North and Middle Norway, and a southern highland population showed the largest expected responses to phenotypic selection for most of the characters. The results demonstrate that there is enough genetic variation in adapted local populations to develop new improved cultivars adapted to high-latitude environments that combine upright growth habit with sufficient winter-hardiness and persistency. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   
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