豫北山区“粮—草—羊”高效平衡养羊模式现状

从粮食作物、经济作物及饲草的种植,饲草料的加工调制与利用,全舍饲肉羊的养殖及杂交繁育,以及羊粪尿的资源化利用等方面介绍了豫北山区“粮—草—羊”高效平衡养羊模式发展现状,以期为促进豫北山区资源可持续利用、山区生态环境良性循环和社会经济可持续发展提供思路。     

Cryptic species and population genetic structure of Plasmopara viticola in São Paulo State,Brazil

Downy mildew (Plasmopara viticola) is one of the most important diseases in grape-growing areas worldwide, including Brazil. To examine pathogen population biology and structure, P. viticola was sampled during the 2015/16 growing season from 516 lesions on nine grape cultivars in 11 locations in subtropical areas of São Paulo State, Brazil. For identification of cryptic species, a subsample of 130 isolates was subjected to cleaved amplified polymorphic sequence (CAPS) analysis, and for 91 of these isolates the ITS1 region was sequenced. These analyses suggest that the population of P. viticola in São Paulo State consists of a single cryptic species, P. viticola clade aestivalis. Seven microsatellite markers were used to determine the genetic structure of all 516 P. viticola isolates, identifying 23 alleles and 55 multilocus genotypes (MLGs). Among these MLGs, 34.5% were clonal and represented 93% of the isolates sampled. Four dominant genotypes were present in at least five different locations, corresponding to 65.7% of the isolates sampled. Genotypic diversity (Ĝ = 0.21–0.89) and clonal fraction (0.58–0.96) varied among locations (populations). Most populations showed significant deviation from Hardy–Weinberg expectations; in addition, excess of heterozygosity was verified for many loci. However, principal coordinate analysis revealed no clusters among locations and no significant isolation by distance was found, suggesting high levels of migration. The results indicate that downy mildew epidemics result from multiple clonal infections caused by a few genotypes of P. viticola, and reproduction of P. viticola in São Paulo State is predominantly asexual.     

PPARγ mediates effects of diosgenin on proliferation and apoptosis in human glioblastoma U87MG cells

AIM:To investigate the effect of diosgenin (Dio) on the proliferation, apoptosis and expression of peroxisome proliferator-activated receptor γ (PPARγ) in human glioblastoma U87MG cells and its possible mechanism. METHODS:Human astrocytes (HA) and U87MG cells were cultured in vitro and treated with Dio (0, 10, 20, 30, 40 and 50 μmol/L) and GW9662 (5 μmol/L) for 48 h, and then the cell viability was detected by CCK-8 assay. Cell colony formation assay was used to assess the proliferation potential. Flow cytometry was used to analyze the cell cycle distribution and apoptosis. The mRNA expression level of PPARγ was measured by RT-PCR. Western blot was used to determine the protein levels of PPARγ, cyclin D1, cyclin E1, Bcl-2 and Bax. RESULTS:Dio had no significant influence on the viabi-lity of HA (P>0.05). However, Dio remarkably reduced the viability of U87MG cells in a dose-dependent manner (P<0.05) with IC₅₀ of 24.31 μmol/L. Meanwhile, Dio remarkably diminished colony formation ability (P<0.05), induced G₀/G₁ phase arrest of the cell cycle and apoptosis (P<0.05), up-regulated the expression of PPARγ at mRNA and protein levels, increased the protein level of Bax (P<0.05), and down-regulated the protein levels of cyclin D1, cyclin E1 and Bcl-2 (P<0.05) in a dose-dependent manner. However, these effects induced by Dio were inhibited by GW9662 (P<0.05), a specific inhibitor of PPARγ. CONCLUSION:Dio may inhibit proliferation and induce apoptosis in human glioblastoma U87MG cells most likely via up-regulating the expression of PPARγ, and then down-regulating the protein levels of cyclin D1, cyclin E1 and Bcl-2, and up-regulating the protein level of Bax.     

茶树新品种--梦茗

"梦茗"系从安徽省岳西县来榜镇优良地方群体种中采用单株选育法育成的适制绿茶新品种。经安徽省内品比、推广示范和全国区试,发现"梦茗"物候期与福鼎大白茶相当,属早生种。品质优异,全国区试3个点感官审评总分均高于对照;内含物含量高,氨基酸含量4.9%、茶多酚总量26.9%、水浸出物总量40%。产量高,品比试验高于福鼎大白茶26.45%,全国区试产量与对照相当。抗旱能力强,抗寒能力与对照相当。     

伐地那非增加EGCG-β-乳球蛋白纳米粒对肝癌细胞的抑制作用

较高浓度的EGCG才能抑制癌细胞的增殖,通过纳米化和EGCG与其他药物的联合使用是提高EGCG生物活性的重要策略。本研究将EGCG和伐地那非（VD）同时包埋于β-乳球蛋白（β-Lg）纳米载体中,制备出EGCG-VD-β-Lg纳米粒（EVβ-NPs）,体外试验证实,EVβ-NPs能提高人肝癌细胞（HepG2细胞）中Caspase-3活性,使HepG2细胞在S期产生明显的阻滞,诱发细胞核分裂,从而导致HepG2细胞凋亡。研究结果表明,将EGCG与微量的VD联合使用,并通过纳米化包埋可以显著提高EGCG的抗癌活性。这一方法在EGCG抗癌制品的开发方面具有潜在的价值。     

白叶枯病菌效应子XopN在拥有OsSWEET11同源基因的水稻品种上发挥毒性作用

【目的】黄单胞菌细胞外泌蛋白质(Xanthomonas outer proteins, Xops)是植物病原黄单胞菌高度保守的毒性效应子或毒性辅助组分,通过细菌Ⅲ型分泌系统分泌到细菌细胞外部,然后转入植物细胞而发挥病理作用。水稻黄单胞菌水稻致病变种即水稻白叶枯病菌的标准菌株PXO99^A分泌的XopN是一种毒性效应子,通过影响寄主免疫反应而使水稻发病。但是,XopN对病菌毒性的影响是否因水稻品种的不同而异,还有待研究。【方法】利用同源双交换技术,先敲除了PXO99^A的XopN基因,获得了∆XopN突变体,又经过遗传互补,得到了回补菌株∆XopN/XopN。通过营养肉汤液体培养,测定了XopN对病菌繁殖能力的影响;根据文献选用14个水稻品种,通过接种实验,测定了PXO99^A对这些品种的毒性与XopN敲除或回补的影响;在XopN发挥毒性作用的水稻品种上,测定了隐性抗病基因OsSWEET11/xa13与显性感病基因OsSWEET11/Xa13受病菌侵染而表达的情况,分析了XopN敲除或回补的影响。【结果】在营养肉汤液体培养过程中,病菌突变体菌株∆XopN的繁殖速度明显低于野生型PXO99^A。PXO99^A、∆XopN和∆XopN/XopN接种水稻后,根据其在水稻叶片组织内的繁殖量及随后产生的白叶枯病症状的严重程度,将供试的14个水稻品种分为两种情况。一是感病程度与病菌XopN是否敲除或回补无关,这有10个水稻品种（IRBB1、IRBB3、IRBB8、IRBB10、IRBB14、IR24、IRBB203、IRBB204、IRBB205和IRBB211）,PXO99^A、∆XopN和∆XopN/XopN对它们的毒性无明显差别。二是XopN对病菌毒性发挥作用的水稻品种,包括高度感病的3个品种（IRBB208、Asominori和日本晴）和低感品种IRBB13。与PXO99^A或∆XopN/XopN相比,∆XopN对这4个水稻品种的毒性大为降低。在IRBB13上,病菌侵染对隐性抗病基因OsSWEET11/xa13在叶片内的表达发生抑制作用,这一效应与XopN的毒性功能相关。相反,日本晴显性感病基因OsSWEET11/Xa13却受病菌侵染的诱导,在叶片内的表达水平大幅度提高。IRBB208和Asominori携带OsSWEET11/Xa13同源基因,该同源基因在叶片内的表达水平也因病菌侵染而大幅提高。在这4个水稻品种上,PXO99^A和∆XopN/XopN能够诱导OsSWEET11/Xa13或其同源基因表达,但∆XopN无此作用。另外,XopN对病菌在非寄主植物烟草上诱发过敏反应有量变贡献,相比PXO99^A或∆XopN/XopN,∆XopN引起过敏反应的程度有所降低。【结论】XopN是一个有限广谱性效应子,在拥有OsSWEET11同源基因的水稻品种上发挥毒性作用。XopN也是病菌繁殖所需要的,对病菌在非寄主植物上诱导过敏反应有一定贡献。     

土壤温度对作物根区环境及玉米根冠生长的调控研究进展

土壤温度对作物的生长发育具有很强的调控作用。在全球气候变化背景下,根区土壤温度对玉米生长的影响及其调控机制已成为当前研究的一个热点。结合目前农业生产中土壤低温和高温对玉米造成危害的现状,从土壤温度对作物根区土壤环境以及玉米根系生长、冠层发育与产量形成的影响方面,综述土壤温度对玉米生长发育调控作用的研究进展,介绍改变土壤温度的措施以及对玉米土壤温度研究的发展方向进行展望,为今后的研究提供参考。     

玉米脱粒破碎率关键影响因子及其最优预测模型研究

子粒破碎率高是当前中国玉米机械收获子粒的重要限制因素,解析破碎率变化原因,建立其简便预测模型是需要解决的重要问题。本文采集7个玉米品种在3个种植密度下组合的果穗,在不同子粒含水率梯度条件下开展单穗脱粒试验。种植密度在6万～9万株/hm2范围内对子粒破碎率没有影响,品种、子粒的含水率、抗侧压碎力和穿刺强度等的影响均达到统计显著水平。品种对破碎率变化的偏贡献率为12.7%,且品种的偏贡献率子粒含水率的偏贡献率抗侧压碎力的偏贡献率穿刺强度的偏贡献率,种植密度的偏贡献率接近于零。破碎率的最优预测因子是穿刺强度,预测模型:破碎率=10.25×0.990穿刺强度,满足破碎率不高于5%约束的穿刺强度值不得低于60 MPa。研究结果可为玉米破碎率预测、宜机收玉米新品种培育与鉴定、脱粒机具设计与制造提供数据支撑和技术参考。     

灌溉量对玉米生育后期脱水阶段子粒水分的影响

以玉米品种先玉335、九圣禾2468为试验材料,测定不同灌溉量处理的玉米生理成熟至田间收获期间子粒含水率的变化。结果表明,生育期等量灌溉和分配灌溉量试验,在9.0×10~4株/hm^2、12.0×10~4株/hm^2种植密度下,灌溉量增加使子粒含水量呈增加趋势,且脱水速率减慢。灌溉量从3 600 m^3/hm^2增至7 200 m^3/hm^2,子粒含水率分别增加0.94~2.87个百分点,差异达显著水平。灌溉量与种植密度双因素辅助试验,在种植密度6.0×10~4株/hm^2至13.5×10~4株/hm^2时,灌溉量从3 000 m^3/hm^2增至6 000 m^3/hm^2,子粒含水率分别增加1.60~5.00个百分点;在灌溉量3 000 m^3/hm^2和6 000 m^3/hm^2条件下,种植密度从6.0×10~4株/hm^2增至13.5×10~4株/hm^2,子粒含水率有差异,无明显增加或降低趋势;4 500 m3/hm^2灌溉量下各种植密度处理间的子粒含水率未表现出显著差异。     

秸秆还田对东北半干旱区玉米‖花生轮作系统土壤水热特性及作物产量的影响

以东北半干旱区玉米‖花生轮作系统为研究对象,试验设传统玉米单作、花生单作、不同秸秆还田量下(30%、60%和100%)玉米‖花生轮作5个处理。通过连续3年田间定位试验,研究玉米秸秆不同还田量对农田土壤水热特性、产量及土地当量比(LER)的影响。结果表明,与传统单作相比,秸秆还田处理玉米区播前0～40 cm土壤平均含水量提高了1.9%～3.9%,花生区提高了11.0%～13.9%;成熟期,秸秆还田花生区0:00～8:00平均地温比传统单作提高了0.2℃～1.1℃,10:00～22:00平均地温较传统单作降低了0.5℃～1.0℃。2016年和2017年玉米‖花生轮作系统LER为1.05～1.16,2018年各处理LER均小于1。吉林半干旱区玉米‖花生轮作系统进行秸秆还田改善了作物播前的土壤水分状况,但对于作物产量的影响在不同年份有所差异。