黄瓜根分泌物中的7,8-苯并黄酮及其对枯萎病发生的影响

分别提取黄瓜枯萎病感病品种津研4号和抗病品种中农10号的根分泌物,感病品种根分泌物甲醇提取液能够刺激枯萎病菌的菌丝生长,而抗病品种根分泌物甲醇提取液则抑制病原菌生长。利用LC-MS/MS技术分别对感病品种和抗病品种根分泌物中的差异物质进行分析鉴定。与感病品种津研4号相比,抗病品种中农10号根分泌物中含有7,8-苯并黄酮(7,8-BF),含量为0.02μg/株。50μg/mL的7,8-BF能够显著抑制黄瓜枯萎病菌菌丝生长和孢子萌发,而100μg/mL的7,8-BF能显著抑制抗感品种侧根形成,但是抗病品种的耐受力高于感病品种。用7,8-BF处理黄瓜种子,枯萎病侵染程度显著降低。当7,8-苯并黄酮浓度为50μg/mL时,感病品种病情指数从71.7降为30.8,达到中抗水平。     

氮肥配施下不同C/N作物残渣还田对红壤温室气体排放的影响

氮肥配施能够促进还田秸秆的分解,为了解其对不同C/N秸秆还田下温室气体排放的影响,采用培养实验方法,研究了油菜饼(C/N为4)、玉米秸秆(C/N为28)、水稻秸秆(C/N为41)和小麦秸秆(C/N为71)等4种不同C/N植物残渣在不同量氮肥(无氮、低氮和高氮)配施下对红壤温室气体(CO2、CH4和N2O)排放的影响。结果显示,氮肥配施增加了不同植物残渣的CO2-C累积排放量,且仅在高C/N的小麦秸秆处理中发现存在显著性差异,在低氮和高氮下CO2-C累积排放量分别达到1 271.44、1 212.83 mg·kg-1,显著高于无氮肥配施的883.40 mg·kg-1。土壤N2O累积排放量最大的为油菜饼处理组,低氮量的配施进一步增强了N2O的产生,其累积排放量达到5 550.42μg·kg-1,显著高于无氮肥配施的4 430.44μg·kg-1,然而当氮肥施用量进一步增加时却抑制了N2O的排放(3752.84μg·kg-1)。氮肥配施并未显著影响玉米秸秆和小麦秸秆处理组的N2O累积排放量。在培养期内,每一个处理均表现为CH4的吸收现象,氮肥施用能够增加土壤对CH4的累积吸收量,但差异显著性仅在对照和油菜饼处理中发现。     

β-carotene attenuates weaning-induced apoptosis via inhibition of PERK-CHOP and IRE1-JNK/p38 MAPK signalling pathways in piglet jejunum

Weaning may cause oxidative injury, immune response impairment, apoptosis and other injuries in piglets. Oxidative and endoplasmic reticulum stress (ERS) can elicit inflammatory responses, and persistent oxidative and ERS also may lead to apoptotic cascades, which is associated with the pathogenesis of multiple diseases. β-carotene, a natural carotenoid, has potential anti-inflammatory and antioxidant functions. However, the effect of β-carotene on apoptosis in weaned piglets and the detailed molecular mechanism remain unclear. In this study, we found that β-carotene decreased malondialdehyde (MDA) levels and increased the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) in piglet serum. β-carotene could inhibit the mRNA levels of caspase-3 significantly, but had no significant inhibitory effect of the mRNA levels of caspase-9 and caspase-12 in the piglet jejunum. In addition, β-carotene decreased the activation of GRP78, CHOP, and JNK/p38 MAPK and the ratio of Bax/Bcl-2. Furthermore, β-carotene had a significant influence on the activation of ERS and apoptosis-related signals in TG-induced IPEC-J2. In the present study, β-carotene pre-treatment attenuated the ratio of Bax/Bcl-2 and prevented TG-induced increases in the level of PERK-CHOP and IRE1-JNK/p38 MAPK pathway activation in a dose-dependent manner. Overall, these findings indicate that β-carotene may protect weaning-induced apoptosis through inhibiting ERS.     

自动配料生产线远程管理系统研究

为实现自动配料生产过程的远程管理及生产现场的无人值守,根据自动配料生产线的特点,设计了一种自动生产配合饲料的远程管理系统。系统采用S7-200 CPU226实现现场设备的控制。通过自由口协议实现与现场监控计算机的通信。监控程序使用VC++.NET开发,并采用客户端/服务器通信模式,实现了自动配料系统的网络化远程管理。采用屏幕切分法进行现场监控画面的及时传输,实现现场设备的实时监控。     

Effects of aerobic conditions in the rhizosphere of rice on the dynamics and availability of phosphorus in a flooded soil – A model experiment

The secretion of O₂ by rice roots results in aerobic conditions in the rhizoshere compared to the bulk flooded soil. The effect of this phenomenon on the adsorption/desorption behavior and on the availability of phosphorus (P) in a flooded soil was investigated in a model experiment. An experimental set‐up was developed that imitates both O₂ release and P uptake by the rice root. The results showed that O₂ secretion significantly reduced P adsorption/retention and increased P desorption/release in the “rhizosphere” soil, compared to the anaerobic bulk soil. The P uptake by an anion exchange resin from both unfertilized and P‐amended soil was significantly increased. The results confirm that the O₂ secretion is an important mechanism to enhance P availability and P uptake of rice under flooded conditions, where the “physico‐chemical” availability of P in the anaerobic bulk soil is strongly reduced. The decrease of P availability in the P‐amended flooded bulk soil was mainly associated with the almost complete transformation of the precedingly enriched Al‐P fraction into Fe‐bound P with extremely low desorption/release characteristics during the subsequent flooding.     

小麦/玉米/大豆和小麦/玉米/甘薯体系中玉米产量及养分吸收的差异

分别在四川2个玉米主产区川中丘区射洪县和川西山区雅安市,采用单因素随机区组设计,通过3年田间试验对比研究了小麦/玉米/大豆和小麦/玉米/甘薯模式下玉米产量、养分吸收积累规律以及与耕层土壤养分的关系。结果表明:两种套作模式经过一年种植后,小麦/玉米/大豆模式下玉米产量均高于小麦/玉米/甘薯模式下的玉米产量,但差异不显著,第二、三年分带轮作后,小麦/玉米/大豆模式下玉米产量显著高于小麦/玉米/甘薯模式下的玉米产量,二年平均分别高出 679.5 kg/hm2和 839.1 kg/hm2,增产9.4%和12.6%,射洪试验点增产作用较雅安试验点显著;分带轮作后两种套作体系玉米氮素吸收积累在拔节前差异不显著,拔节后小麦/玉米/大豆模式下玉米氮素积累量显著高于小麦/玉米/甘薯,磷的吸收积累则相反,从拔节期到开花期,小麦/玉米/大豆模式下玉米磷的吸收积累均显著低于小麦/玉米/甘薯,小麦/玉米/大豆模式下玉米钾素吸收积累量高于小麦/玉米/甘薯;不同作物带耕层土壤养分含量差异达显著水平,大豆带残留的硝态氮、速效氮、速效钾2个试验点平均分别比甘薯带高18.4%、24.1%、6.0%,而铵态氮和速效磷甘薯带较大豆带分别高18.9%和17.1%,两种套作模式中玉米带耕层土壤养分含量差异不显著,经第二、三年分带轮作后,耕层土壤养分含量差异减小,表明分带轮作玉米能较好均衡田间养分。     

有机肥对混推复垦地养分变化及生产力的影响

以混推复垦地为研究对象,通过对土壤养分的变化、作物长势和产量(生产力)及其经济效益进行分析比较,结果表明,增施有机肥量为18500,11000kg/hm2时,不论增施1年还是2年,仅表现出0～20cm土壤有效P显著高于对照(CK);增施有机肥量为11000kg/hm2时,不论增施1年还是2年,玉米株高在苗期、拔节期和抽雄期均显著高于对照(CK),且玉米产量和秸秆产量也表现出最高;增施有机肥量为11000kg/hm2时,连续2年的累计经济效益最优。     

GC/MS法研究猪体内盐酸克伦特罗的残留代谢规律

样品用乙酸乙酯提取,盐酸溶液萃取后,再经SCX固相萃取柱净化,50℃水浴中氮气吹干后衍生化。以气相色谱-质谱选择86、212、262、277四个碎片离子进行定性定量分析。盐酸克伦特罗在0.01～2.0 mg/L成线性（R2为0.999）,猪肉中3种不同添加浓度0.01、0.10和0.20mg/kg下克仑特罗平均回收率分别为88.31%、92.85%、93.97%,相对标准偏差分别为5.26%、7.58%、4.59%,样品中最低检测限（S/N=3）为0.1 ug/kg。应用该方法研究了克仑特罗在猪体内的消除并初步探讨其代谢机理。结果表明,在饲喂浓度（3 mg/kg）1个月后,猪体内盐酸克伦特罗蓄积量不算太高,最高蓄积浓度为493.59 ug/kg,而且停药后代谢又非常快。     

树皮内含物对香梨优斑螟寄主选择的影响

为了明确香梨优斑螟的寄主选择和寄主树皮内含物对寄主选择的影响,调查研究野外香梨优斑螟在不同寄主植物上的危害情况和室内幼虫的取食选择,并对寄主植物树皮中几种内含物含量与香梨优斑螟的寄主选择关系进行分析。结果表明:在野外,不同寄主植物的受害率、平均虫口数及最大虫口数,均为香梨树苹果树枣树,但枣树的蛹与幼虫的比值高于苹果;室内幼虫取食选择试验,幼虫对4种寄主植物的选择存在显著差异,香梨树枣树砀山梨树苹果树,推测枣树为香梨优斑螟潜在的高风险寄主。香梨优斑螟幼虫的寄主选择与单一的可溶性糖、可溶性蛋白、总糖、氨基酸和单宁含量均无显著相关,与4种树的碳氮比(r=-0.960,P0.05)和总酚含量(r=-0.900,P0.05)呈显著负相关,均衡的营养和较低的取食抑制物含量是香梨优斑螟选择寄主植物的标准。     

抗病增丝剂在蚕体内分布规律的研究

用~3H 标记抗病增丝剂,给5龄家蚕进行添食处理,以测定抗病增丝剂在家蚕体内及丝茧中的吸收和分布规律。结果表明,抗病增丝剂主要分布在绢丝腺和茧层中,而蛹体内则甚微.