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排序方式: 共有498条查询结果,搜索用时 15 毫秒
1.
乙烯利对干旱胁迫下草地早熟禾生理指标的影响   总被引:1,自引:0,他引:1  
以草地早熟禾(Poa pratensis)‘Nuglade'品种为试验材料,研究叶片喷施乙烯利对草地早熟禾在水分充足、干旱及复水恢复3种处理下叶片电解质渗透率、叶绿素、可溶性蛋白、丙二醛(MDA)等生理指标的影响。结果表明,乙烯利与对照组(CK)相比,乙烯利在干旱胁迫下保持更高的叶片相对含水量23.5%(对照为11.5%)和更低的电解质渗透率68.1%(对照为90.7%)及MDA含量53.90μmol·g~(-1)(对照检查131.62μmol·g~(-1)),且复水后的电解质渗透率恢复程度更好;此外乙烯利处理提高了复水恢复过程草地早熟禾的可溶性蛋白含量;说明,叶片喷施乙烯利能够缓解草地早熟禾的干旱胁迫损伤,并促进干旱后的复水恢复。  相似文献   
2.
The aim of this study was to evaluate the effects of dietary betaine (BET) on growth performance, redox state, and related gene expression in broilers under heat stress (HS). A total of 144 21-day-old male broiler chickens with similar body weights were assigned randomly to three treatments with six replicates (eight chickens per replicate cage). Broilers in the control (CON) group were kept at thermoneutral (TN, 22±1°C) conditions and fed a basal diet until they were 42 days of age. Broilers in the other two groups (defined as HS and HS + BET) were exposed to HS (34±1°C, 8 h/day) and fed the basal diet without or with 1000 mg/kg BET, respectively. Rectal and cockscomb temperature of broilers was increased (P<0.05) in HS and HS + BET groups compared with the CON group, whereas there was no difference between HS and HS + BET groups. Dietary BET supplementation restored (P<0.05) average daily gain (ADG) and average daily feed intake (ADFI) of broilers and reversed (P<0.05) the increase in serum alanine transaminase (ALT) activity and malondialdehyde (MDA) content in the liver tissue of broilers under HS. The HS + BET group had higher (P<0.05) activities of superoxide dismutase (SOD) and glutathione peroxidase (GPX) in the liver tissue and mitochondria than the HS group, and the same pattern was observed for glutathione (GSH) and GSH/glutathione disulphide (GSSG) in the liver tissue. The decreased mRNA levels of GPX1 and uncoupling protein (UCP) in the liver induced by HS were restored by BET supplementation. In conclusion, dietary BET supplementation can alleviate HS-induced hepatic and mitochondrial oxidative damage of broilers by regulating mRNA expressions of GPX1 and UCP.  相似文献   
3.
MYB转录因子家族基因具有保守的DNA结合域,是植物最大的转录因子家族之一,广泛参与植物的代谢调控,在植物生长发育和胁迫响应等方面发挥重要作用。为改良品种性状和提高生产实践能力,本研究采用RT-PCR法克隆蒺藜苜蓿MYB转录因子基因MtMYB,其编码区长255 bp,编码84个氨基酸。生物信息学分析表明,该基因编码蛋白与其他物种MYB蛋白具有很高的同源性,其中与红三叶同源性最高。荧光定量结果表明,MtMYB基因在蒺藜苜蓿叶片中的表达量最高。MtMYB基因在外源IAA、6-BA的诱导下,总体都呈现先上升后下降的趋势。同时本研究成功构建35S::MtMYB的植物表达载体,并通过转基因技术将其转化至拟南芥中,PCR检测表明,MtMYB已成功整合至转基因拟南芥基因组中。RT-PCR检测表明,MtMYB能够在转基因拟南芥中正常转录。本研究为进一步探明MtMYB基因的功能提供了数据参考和实验材料。  相似文献   
4.
The feeding trial was conducted to evaluate the potentials of Clostridium butyricum in the diet of tilapia. Fish (~14 g) were fed with basal diet supplemented with 0 (Control), 0.5 (C‐1), 1 (C‐2), 2 (C‐3), 4 (C‐4) and 8 (C‐5) g/kg commercial probiotic‐containing C. butyricum (1.5 × 108 CFU/g) for 8 weeks. The results showed that weight gain significantly increased, and feed conversion ratio decreased in the C‐2, C‐3 and C‐4 groups (p < .05). The protein retention (except C‐1 group), lipid retention and apparent digestibility coefficient (ADC) of dry matter in probiotic supplementation groups were significantly enhanced, and ADC of protein in the C‐4 group was also improved (p < .05). The supplementation of probiotic significantly increased villus height in anterior intestines and reduced the numbers of intestinal Escherichia coli (p < .05). High‐throughput sequencing showed that top three phyla namely Planctomycetes in all probiotic‐containing groups, Proteobacteria in the C‐1 and C‐2 groups and Chloroflexi in the C‐3 group had higher level than the NC group. The cumulative mortality was reduced by dietary probiotic after challenging with Aeromonas hydrophila (p < .05). In conclusion, C. butyricum can be supplemented at 1–2 g/kg feed for promoting the growth, feed utilization, gut health and microbiota of tilapia.  相似文献   
5.
This study was conducted to investigate the effects of replacing fish meal (FM) with fermented soybean meal (FSM) and soybean meal (SM) on growth performance, intestinal histology and microbiota of largemouth bass (Micropterus salmoides). The basal diet contained 350 g/kg FM (CON), and then, FM was replaced with SM and FSM at the ratios of 30% and 60% (SM‐30, SM‐60, FSM‐30 and FSM‐60), respectively. The largemouth bass (4.43 ± 0.13 g) were fed for 8 weeks. The results showed that weight gain of fish fed with FSM‐60 and SM‐60 diets was significantly lower, and feed conversion ratio of SM‐30, SM‐60 and FSM‐60 groups was significantly higher than the CON group (p < .05). The intestinal villus height of SM‐60 group and the villus width of SM‐60 and FSM‐60 group were significantly lower than the CON group (p < .05). The 30% FM replacement by SM and FSM significantly increased the abundance of Cetobacterium and Mycoplasma, respectively (p < .05). In conclusion, FSM could replace 30% FM in diet without negative impacts on the growth performance of largemouth bass, while the SM should be controlled below 30%.  相似文献   
6.
日本对虾越冬亲虾性腺促熟及工厂化育苗技术研究   总被引:1,自引:0,他引:1  
1997、1998年利用越冬亲虾进行性腺促熟,用镊烫法切除眼柄,促进亲虾发育。结果:两年共培育亲虾雌虾8204尾。雄虾5683尾,获交尾虾5360尾。交尾率为71.81%。每年两批育苗,共利用水体1720m~3,育出0.7~1.1cm的虾苗12450万尾,平均单位水体出苗量为7.24万尾/m~3,效益显著。  相似文献   
7.
口感好硒含量高采摘期长,这是海南省“澄迈福橙”的特点,澄迈县将福橙促销瞄准大超市。2009年2月20日,该县在省城海口市召开福橙品尝推介会,向超市促销这一地方名牌农产品。  相似文献   
8.
轴流泵叶轮进出口流场的测量   总被引:5,自引:0,他引:5  
为了获得轴流泵内部流动的真实情况,设计了内部流动测量装置.运用五孔球形探针,对高效轴流泵在0.8Qopt,1.0Qopt和1.2Qopt工况下的叶轮进口和出口速度矢量分布、静压分布和总压分布进行了测量,并分析了不同工况下的轴面速度、环量、圆周方向分速度和压力分布等.测量结果表明:轴流泵模型进口在0.8Qopt至1.2Qopt工况范围内,流动稳定,进口轴向速度从轮毂到轮缘逐渐减小,且进口预旋很小,不同径向位置的静压基本相等.在最优工况下,轮毂与可调叶片间无间隙时,轴流泵叶轮出口基本呈现等环量流型,轴面速度呈现抛物线分布,且效率高.若轮毂侧存在间隙,间隙处的环量、轴面速度、压力和效率均明显下降.  相似文献   
9.
This study was conducted to evaluate the effects of extruded diets and pelleted diets with varying dietary lipid levels on growth performance and nutrient utilization of tilapia. Six diets, containing three levels of lipid at 40, 60 or 80 g kg?1 (with the supplemental lipid of 0, 20 or 40 g kg?1, respectively), were prepared by extruding or pelleting and then fed to tilapia juveniles (8.0 ± 0.1 g) in cages (in indoor pools) for 8 weeks. The results indicated that the fish that were fed the diet with 60 g kg?1 of lipid had a higher weight gain (WG), specific growth rate (SGR), protein efficiency ratio (PER), lipid retention (LRE), energy retention (ERE), apparent protein digestibility, apparent dry matter digestibility and a lower feed conversion ratio (FCR) than those fed the diet with 40 g kg?1 lipid in both the extruded diet and pelleted diet (P < 0.05). As the dietary lipid level increased from 60 to 80 g kg?1, these parameters were not further improved, even digestibilities of the crude protein and dry matter decreased (P < 0.05). With the dietary lipid level increased, whole‐body lipid content significantly increased (P < 0.05), serum aspartate aminotransferase, alkaline phosphatase, total cholesterol and low‐density lipoprotein cholesterol (LDL‐C) tended to increase (P > 0.05), whereas whole‐body protein content, serum triglyceride (TG), high‐density lipoprotein cholesterol (HDL‐C) and HDL‐C/LDL‐C tended to decrease (P > 0.05). Fish fed with the extruded diets had a higher WG, SGR, hepatosomatic index (HSI), PER, protein retention (PRE), LRE, ERE, TG, apparent digestibility of protein and dry matter, as well as a lower FCR, than those fed with the pelleted diets at the same dietary lipid level (P < 0.05). These results suggested that tilapia fed with the extruded diets had a better growth and higher nutrient utilization than fish fed with the pelleted diets, when dietary lipid level ranged from 40 to 80 g kg?1 and at dietary crude protein level was 280 g kg?1. The optimum dietary lipid level was 60 g kg?1 in both the pelleted and extruded diets, and extrusion did not affect dietary lipid requirement of the tilapia.  相似文献   
10.
近红外光谱技术及其在农作物中的应用   总被引:7,自引:2,他引:7  
本文阐述了近红外光谱技术的原理与方法,并对近红外光谱技术在农作物领域的应用研究进行了介绍。  相似文献   
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