外源硒处理对优质地方水稻品种产量及稻米硒氮磷钾含量的影响

旨在研究外源硒处理对不同类型优质地方常规稻产量及硒氮磷钾含量的影响。以籼稻品种(‘泰选1号’)和粳稻品种(‘粳选1号’)为材料,采用完全随机设计,于较高海拔山区试验田(800 m以上)进行不同浓度硒处理试验。结果表明:施用外源硒处理后不会降低两个品种的稻谷产量;随外施硒浓度的提高,两个水稻品种精米及米糠硒含量均显著提高,粳稻品种在0~15 g/hm2外源硒浓度范围内随硒浓度的增加,精米中硒含量的增加率呈较高的线性模式增长;而高浓度硒处理下,粳稻精米率、整精米率显著降低;随外施硒浓度的增加,水稻精米中氮钾元素含量与硒含量从极显著正相关变为极显著负相关。在硒浓度较低的环境下,适当增加氮、钾肥的施用量能促进水稻对硒元素的吸收积累,高浓度反之。因此,对优质地方常规稻外施硒以提高品质与硒元素积累的研究是可行的。     

盐份浓度对油菜干物质积累分配、农艺性状及品质的影响

为了研究不同土壤盐份浓度对油菜生长的影响,2015—2016年度以‘扬油9号’和‘苏油211’为供试品种,在低盐浓度(2.978 g/kg)和高盐浓度(4.900 g/kg)试验田进行种植,于成熟期取样测定植株干物质积累量、农艺性状及籽粒品质含量。结果表明,随着盐份浓度增加,全株及不同器官干物质积累量均显著降低,高盐与低盐处理相比,‘扬油9号’和‘苏油211’产量下降幅度分别为24.14%和27.83%,不同器官中根系干物质积累量下降幅度最大,‘扬油9号’和‘苏油211’根系干物质下降幅度分别为34.52%和39.69%,茎枝干物质积累下降幅度最小,两品种下降幅度分别为9.46%和12.93%。随着盐份浓度增加,茎枝干物质分配比例显著增加,其余器官干物质分配比例均显著降低。随着盐份浓度增加,株高和角果数显著降低,而每角粒数和千粒重在不同盐份浓度处理间无显著差异。随着盐份浓度增加,籽粒油份含量显著降低,蛋白质含量显著增加。     

安徽省作物养分供需分析及化肥减施潜力研究

有机-无机相结合的农田养分管理模式是现阶段中国发展绿色农业的必由之路,因而开展有机、无机养分和作物养分需求的比较研究对促进养分资源的合理分配和施用具有重要的参考价值。本文采用文献调查和统计分析的方法,评估了安徽省16市2010—2016年主要有机肥(包括秸秆、粪便、绿肥和饼肥)的养分资源,明晰了安徽省农业生产中有机、无机养分投入现状,并根据农业种植结构开展了有机、无机养分和作物养分需求的差异和关系研究,最后探索了安徽省的化肥减施潜力。结果表明:安徽省2010—2016年平均有机肥养分资源为287.70万t,N、P_2O_5和K_2O分别为104.49万t、39.60万t和143.61万t,可基本满足作物的养分需求;但有机肥的当季利用率低,N、P_2O_5和K_2O的当季利用率分别为21.44%、19.91%和52.61%,有机肥N、P_2O_5和K_2O实际还田量仅占作物养分需求的20.74%、25.38%和63.61%,占农田养分总投入的比重分别为11.87%、10.27%和51.35%。全省N、P_2O_5、K_2O养分实际投入量(包括有机肥和化肥)是作物养分需求的1.75倍、2.47倍和1.24倍,有7个市的N和13个市的P_2O_5养分施用量超过作物需求的2倍,存在较高的环境污染风险。通过控制农业总养分输入,安徽省的化肥减施潜力为35.12%,N、P_2O和K_2O的减施潜力分别为21.28%、23.97%和78.61%。提高有机肥的当季利用率和发展冬季绿肥资源可进一步促进化肥减施。本研究可为安徽省化肥零增长和农牧业的绿色可持续发展提供数据参考。     

豌豆的生长潜能研究

应用一种较适于植物根域环境优化的技术即平台式水平放任栽培技术来进行豌豆的水气培,通过试验研究表明豌豆能在这种环境下表现出超常规发育的生长特性,如单株产量、总体生物量、有效生物转换率、枝蔓叶荚的形态等都发生了巨大变化,使生物量数十倍的提高,使植株发育表现出巨大化与树型化。可以利用该技术栽培出极具观光价值的豌豆树与其他种类繁多的蔬菜树。     

两个氮素利用率不同的水稻品种根系形态及生理特性的差异

The variation in nitrogen (N) uptake by rice has been widely studied but differences in rice root morphology that may contribute to this variation are not completely understood. Field and greenhouse experiments were carried out to study N accumulation, root dry weights, total root lengths, root surface areas, and root bleeding rates of two rice cultivars, Elio with low N-use efficiency and Nanguang with high N-use efficiency. Low (1 mmol N L^-1) and high (5 mmol N L^-1) N applications were established in the greenhouse experiment, and the N rates were 0, 120, and 240 kg ha^-1 in the field experiments at Jiangning and Jiangpu farms, Nanjing, China. The results showed that the N accumulation, root dry weight, total root length, and root surface area increased with an increase in N application. At the heading stage, N accumulation in the shoots and roots of Nanguang was greater than that of Elio in the field experiments and that of Elio at 5 mmol N L^-1 in the greenhouse experiment. After the heading stage, N accumulation was higher for Nanguang at both 1 and 5 mmol N L^-1 in the greenhouse experiment. The total root length and root surface area were significantly different between the two cultivars. Over the range of the fertilizer application rates, the root lengths of Nanguang at Jiangning Farm were 49%-61% greater at booting and 26%-39% greater at heading than those of Elio, and at Jiangpu Farm they were 22%-42% and 26%-38% greater, respectively. Nanguang had a greater root bleeding rate than Elio. It was concluded that the N-use efficiency of the two rice cultivars studied depended to a great extent on the root morphological parameters and root physiological characteristics at different growth stages.     

长期用生活污水处理厂排放的废水浇灌影响了糙米和土壤中重金属的含量

A pot experiment was conducted in a plastic film house to evaluate the translocation and uptake of heavy metals(Pb,Cd,Cu,and Zn) into brown rice(Oryza sativa L.) and the heavy metals residues in soils which had previously been irrigated with domestic wastewater for a long time(3 years).The range of Pb,Cd,Cu,and Zn was 5.10 ± 0.01,0.105 ± 0.017,5.76 ± 0.42,and 23.56 ± 1.40 mg kg-1,respectively in the domestic wastewater-irrigated soil,and 0.370 ± 0.006,0.011 ± 0.001,0.340 ± 0.04,and 2.05 ± 0.18 mg kg-1,respectively,in the domestic wastewater-irrigated brown rice.The results indicated that application of domestic wastewater to arable land slightly increased the levels of Pb,Cd,Cu,and Zn in soil and brown rice(P < 0.01).The concentrations of heavy metals in brown rice were lower than the recommended tolerable levels proposed by the Joint FAO/WHO Expert Committee on Food Additives.However,the continuous monitoring and pollution control of hazardous materials from domestic wastewater are needed in order to prevent excessive build-up of heavy metals in the food chain.     

隆玉2号玉米干物质积累与养分吸收特性研究

在中等土壤肥力下对隆玉2号玉米的干物质积累与养分吸收特性进行研究。试验结果表明,植株干物质和养分吸收量随着生育期延长而持续增加,动态变化可用Logistic方程拟合;干物质积累速率前期上升快,至高峰后缓慢下降;氮、钾吸收速率高,上升快,下降也快。磷吸收速率低,上升慢,下降也慢;养分最大吸收速率出现的时间,钾最早,氮次之,磷最晚,但均早于干物质最大积累速率出现时间;抽雄吐丝后N、P2O5主要分配在籽粒中,而K2O在籽粒中的分配量很少;干物质、N、P2O5、K2O的转移率分别为14.28%、40.41%、47.47%、37.04%;每100 kg籽粒吸N 1.65 kg、P2O50.56 kg、K2O 1.40 kg;较佳的施肥方法是:氮肥要多次分期施用,“适量种肥、前轻、中重、后补”;磷肥作基肥或种肥一次施用;钾肥要求“适量种肥,前轻中重”,最好在抽雄吐丝前全部施完。     

Dynamic Changes in the Calcium Content of Several Apple Cultivars During the Growing Season

Dynamic changes in calcium content were investigated in eight apple cultivars. The results showed that the calcium concentration in leaves and shoots increased with fruit development. The cultivars displayed only a small difference in the calcium concentration during the early stage of development, the difference became very significant at the late stage of development, especially in shoots. In shoots, for example, calcium content was highest in Starkrimson （19 638.6 mg kg^-1） and lowest in Fuji （8 751.3 mg kg^-1）. Calcium concentration was highest in young fruits and was found to decrease with the growth of fruit, and was characterized by a dramatic drop at the rapid expansion stage. There was a significant difference among cultivars. Young Starkrimson fruits contained the highest calcium concentration of 506.52 mg kg^-1 among cultivars tested, followed by Pink Lady and Fuji. The calcium concentration in mature fruits from high to low is as follows： Starkrimson, Sansa, Pink Lady, Senshu, Gala, Fuji, Red General and New Century. In this study, it was found that eight cultivars continuously assimilated calcium during the whole growing season, especially at the young stage when fruit took up 35-46% of total calcium. The calcium content in fruitlets was low in all cultivars; in the expansion stage, there was rapid absorption of about 30% of total calcium, whereas in the ripening fruit, content of calcium was reduced. The calcium accumulation increased with fruit growth in stalk, similar to that in fruit.     

减源对超高产夏玉米物质积累及氮素利用的影响

通过不同减源处理,研究了在超高产条件下减源对夏玉米物质积累和氮素利用的影响。结果表明：在超高产条件下剪叶1／4和1／2后地上部生物量和籽粒产量未出现显著性下降;减源后玉米植株对氮素的积累量增加;超高产条件下剪叶1／4和1／2都可以提高氮素收获指数,且随剪叶程度加大,氮素收获指数呈现升高的趋势。选育高产条件下叶面积相对小的高产夏玉米品种,是解决高产条件下氮素利用率低的有效途径。     

二维空间完备性基本定理的相互证明

平面上的5个定理,闭区域套定理,有限覆盖定理,聚点定理,致密性定理及Cauthy准则,刻画了R2的完备性,构成了二元函数极限理论的基础.分别以闭区域套定理,有限覆盖定理,聚点定理为基础,证明其它定理,体现了这5个定理之间的相互等价.