Plant regeneration via protoplast electrofusion in cassava

Protoplast electrofusion between callus protoplasts of cultivar TMS60444 and mesophyll protoplasts of cultivar SC8 was performed as an approach for the genetic improvement of cassava. The fusion products were subsequently cultured in protoplast culture medium(TM2 G) with gradual dilution for approximately 1–2 months. Then the protoplast-derived compact calli were transferred to suspension culture medium(SH) for suspension culture. The cultured products developed successively into embryos, mature embryos, and shoots on somatic embryo emerging medium(MSN), embryo maturation medium(CMM), and shoot elongation medium(CEM), respectively. And the shoots were then rooted on Murashige and Skoog(1962) medium(MS). Sixty-six cell lines were obtained and 12 of them developed into plantlets. Based on assessment of ploidy level and chromosome counting, four of these plantlets were tetraploid and the remaining eight were diploid. Based on assessment of ploidy level and simple sequence repeat(SSR) analysis, nine tetraploid cell lines, one diploid variant plant line and nine variant cell lines were obtained. The diploid variant plant line and the nine variant cell lines all showed partial loss of genetic material compared to that of the parent TMS60444, based on SSR patterns. These results showed that some new germplasm of cassava were created. In this study, a protocol for protoplast electrofusion was developed and validated. Another important conclusion from this work is the confirmation of a viable protocol for the regeneration of plants from cassava protoplasts. Going forward, we hope to provide technical guidance for cassava tissue culture, and also provide some useful inspiration and reference for further genetic improvement of cassava.     

黑龙江省主要农业气象灾害及防灾减灾措施

针对黑龙江省频发的干旱、暴雨洪涝、霜冻、风雹等农业气象灾害进行分析,并提出切实可行的防灾减灾措施,为相关部门制定农业生产决策提供科学依据。     

农田尾菜发酵过程中农药残留变化特征

基于尾菜中存在农药残留的现状,以设施农业尾菜黄瓜秧为研究对象,采用气相色谱法和超高效液相色谱-串联质谱法检测了尾菜黄瓜秧在静态好氧发酵过程中多菌灵、吡虫啉、哒螨灵等50种农药残留的动态变化,并分析发酵重要影响因子堆高对农药残留消解的影响。结果表明:在尾菜黄瓜秧中共检测出腐霉利、多菌灵、嘧菌酯、苯醚甲环唑、烯酰吗啉、虫螨腈、吡虫啉、啶虫脒和哒螨灵9种农药残留,其中多菌灵平均残留量最高,达11.2 mg/kg,其他8种农药平均残留量在0.042~0.89 mg/kg之间。在发酵的24 d中,不同堆高条件下9种农药的消解规律均符合一级反应动力学方程,但不同农药半衰期差异较大,其中吡虫啉的平均半衰期最长,为28.9 d,多菌灵的平均半衰期最短,为10.2 d;不同堆高处理中农药的消解速率也有差异,总体上在2.5 m堆高下各农药的消解率最高、半衰期最短。本研究结果可为尾菜发酵参数优化、农业废弃物的高效资源化利用以及研发基于尾菜发酵产物的有机蔬菜专用有机肥提供理论支撑。     

新单系列玉米品种的遗传基础解析以及品质和产量性状变化趋势分析

为探索新单系列玉米品种籽粒品质性状之间的关系以及产量性状的变化趋势,以新乡市农科院2003年以来审定的玉米品种为材料,研究了它们的遗传基础、杂优模式、品质性状以及群体、个体生产力。结果表明：13个玉米品种利用的杂优模式主要有2种,9个品种杂优模式为改良Reid×唐四平头,4个品种为外来种质×唐四平头。品质分析中,‘新单28’、‘新单38’、‘新单66’粗淀粉含量高,‘新单61’、‘新单65’和‘新单68’的粗蛋白和赖氨酸含量高。粗脂肪含量和粗淀粉含量之间呈显著负相关,相关系数为0.610,粗蛋白含量和赖氨酸含量之间呈显著正相关,相关系数为0.491。产量分析表明,‘新单22’单株生产力最大,‘新单33’单株生产力最小,‘新单58’的群体生产力最大,‘新单28’的群体生产力最小。群体生产力随密度增加呈现上升趋势,其中密度为75000株/hm²时的群体生产力较45000株/hm²高62.9%,平均每公顷增加7500株产量增益为12.97%。单株生产力随密度增加开始呈下降趋势,增至60000株/hm²后逐渐平缓,低密度时单株生产力较高密度高5.5%。外来种质×唐四平头杂优模式选育的玉米新品种在品质上优于改良Reid×唐四平头模式选育的品种,且耐密性也显著增加,群体生产力也不断上升。     

国内土壤环境污染防治进程及展望

综述以中国2005—2019年土壤污染防治进程的3个阶段为主线,总结土壤污染防治发展过程中管理模式、治理体系、管控要求、机构改革、立法支持等5个方面重要转变,分析国家和地方土壤环境保护标准、法律法规政策和主要土壤污染治理成效。针对国内土壤污染防治未来发展趋势,从完善土壤环境标准及管理制度、建设监测及预警大数据平台、加强土壤生态环境国际合作、持续推进土壤修复技术攻关和先行区经验推广等方面提出建议,以期为生态环境高水平保护和经济社会高质量发展提供参考。     

核桃嫩枝扦插影响因子的研究

为了探索核桃嫩枝扦插影响因子,提高生根率,采用L9(34)正交试验方法,开展嫩枝扦插试验研究.结果 表明,高湿腐烂是影响核桃扦插是否成功的主要因素,插穗基部采用低浓度高锰酸钾浸泡,并补充吲哚丁酸钾和蔗糖,每天少量喷雾保湿,可以实现核桃嫩枝扦插生根率53.33％.最优方案为:基质采用珍珠岩或蛭石,插穗基部在50 mg/L高锰酸钾浸泡12h,然后补充0.04％吲哚丁酸钾和1％蔗糖6h,喷雾间隔时间为6h喷雾1min.     

Relay-intercropping soybean with maize maintains soil fertility and increases nitrogen recovery efficiency by reducing nitrogen input

Optimized nitrogen(N)management can increase N-use efficiency in intercropping systems.Legume-nonlegume intercropping systems can reduce N input by exploiting biological N fixation by legumes.Measurement of N utilization can help in dissecting the mechanisms underlying N uptake and utilization in legume-nonlegume intercropping systems.An experiment was performed with three planting patterns:monoculture maize(MM),monoculture soybean(SS),and maize-soybean relay intercropping(IMS),and three N application levels:zero N(NN),reduced N(RN),and conventional N(CN)to investigate crop N uptake and utilization characteristics.N recovery efficiency and 15N recovery rate of crops were higher under RN than under CN,and those under RN were higher under intercropping than under the corresponding monocultures.Compared with MM,IMS showed a lower soil N-dependent rate(SNDR)in 2012.However,the SNDR of MM rapidly declined from 86.8%in 2012 to 49.4%in 2014,whereas that of IMS declined slowly from 75.4%in 2012 to 69.4%in 2014.The interspecific N competition rate(NCRms)was higher under RN than under CN,and increased yearly.Soybean nodule dry weight and nitrogenase activities were respectively 34.2%and 12.5%higher under intercropping than in monoculture at the beginning seed stage.The amount(Ndfa)and ratio(%Ndfa)of soybean N2 fixation were significantly greater under IS than under SS.In conclusion,N fertilizer was more efficiently used under RN than under CN;in particular,the relay intercropping system promoted N fertilizer utilization in comparison with the corresponding monocultures.An intercropping system helps to maintain soil fertility because interspecific N competition promotes biological N fixation by soybean by reducing N input.Thus,a maize-soybean relay intercropping system with reduced N application is sustainable and environmentally friendly.     

包膜甜菜碱与有机铬复合物对夏季奶牛产奶性能和血液生化指标的影响

旨在研究包膜甜菜碱和有机铬复合物对夏季奶牛产奶性能和血液生化指标的影响。选择年龄、胎次、泌乳时间和产奶量相近100头泌乳牛,随机分为对照组和试验组,每组50头,对照组饲喂原奶牛场配方日粮,试验组在每天早晨TMR日粮中添加50 g/d包膜甜菜碱和有机铬复合物。结果:与对照组相比,试验组奶牛采食量显著提高(P<0.05),牛奶中体细胞含量显著降低(P<0.05);奶牛乳酸脱氢酶(LDH)含量显著提高(P<0.05);磷酸肌酸激酶(CPK)含量显著降低(P<0.01),谷胱甘肽过氧化物酶(GSH-PX)、超氧化物歧化酶(SOD)含量有上升趋势,丙二醛(MDA)、碱性磷酸酶(ALP)含量有下降趋势,但差异均不显著。试验表明包膜甜菜碱和有机铬具有提高热应激期奶牛采食量、促进代谢和蛋白质合成、缓解奶牛热应激的作用。