不同施肥措施对冬小麦灌浆期氮素吸收分配的影响

以黄淮海平原国家潮土土壤肥力与肥料效益长期监测站为平台,研究了长期不施肥(CK)、氮钾配施(NK)、氮磷钾配施(NPK)、氮磷钾配施有机肥(MNPK)或秸秆(SNPK)5种施肥措施对灌浆期冬小麦吸收利用氮素的影响.研究结果表明,在等氮量条件下,施氮量为N 165 kg/hm2时,NPK、MNPK、SNPK处理有利于小麦在灌浆阶段维持田间较高的群体数和干物质的积累量;其中MNPK、SNPK处理较NPK处理有利于小麦灌浆阶段在茎、鞘器官的生长和干物质积累.在氮素吸收方面,NPK、MNPK、SNPK处理有利小麦灌浆期茎、叶、鞘、穗等器官对氮素的吸收、分配和累积.与CK处理相比,施无机氮、有机氮分别为N 49.5、115.5 kg/hm2时,MNPK、SNPK处理可以延长灌浆高峰期7天左右;而施无机氮为165 kg/hm2时,与CK处理相比,NPK、NK处理可以延长14天左右.在花后1 ～ 14天,MNPK、SNPK处理在茎、穗部位氮素吸收累积量要高于NPK处理,其中穗部差异分别达到P≤0.05显著水平、P≤0.01极显著水平;在花后21 ～ 35天,NPK处理在叶、籽粒部位氮素吸收累积量要高于MNPK、SNPK处理,其中叶部差异均达到P≤0.05显著水平或P≤0.01极显著水平.此外,在灌浆期MNPK处理在穗部氮素累积量要高于SNPK处理.总之,在本试验条件下,无机有机肥配施应适当加大无机氮肥的供应量以弥补小麦灌浆中后期起氮肥供应不足的现象.     

Investigating the effect of Azospirillum brasilense and Rhizobium pisi on agronomic traits of wheat (Triticum aestivum L.)

ABSTRACT

Plant growth-promoting rhizobacteria (PGPR) play an important role in improving crop growth but have not been studied sufficiently. A wire house experiment was conducted in Pakistan to determine the combined effect of inoculating wheat seeds with PGPR on the subsequent growth and yield of the wheat. The experiment included four treatments: T_{0 –} no-inoculation (control), T₁ – Azospirillum brasilense inoculation, T₂ – Rhizobium pisi inoculation and T₃ – co-inoculation with A. brasilense and R. pisi. Development and growth attributes, as well as final yield of wheat, were studied. Co-inoculation of seeds with both strains increased significantly wheat grain yield, the number of grains per plant and 1000-grain weight by 36%, 11% and 17%, respectively, compared to non-inoculated control. While crop growth rate increased for, respectively, 5.5% and 33% at tillering and flag leaf stages, corresponding values for T₃ were about 9% and 14% higher than values for sole inoculations in T₁ and T₂. Co-inoculation also significantly increased leaf epicuticular wax and relative water content as compared to the control treatment. Thus, inoculation of wheat seeds with A. brasilense and R. pisi and their combination is a promising method to improve growth, yield and quality of wheat.     

Foliar resistance to the late blight pathogen Phytophthora infestans (Mont.) de Bary in a backcross of potato (Solanum tuberosum L.) cultivar Ando

ABSTRACT

Regardless of variable environmental conditions and changing pathogen populations, the Estonian potato cultivar (cv.) Ando has shown elevated field resistance to Phytophthora infestans for over 40 years. One of cv. Ando’s parents, the Latvian cultivar Agra, is considered a cultivar of medium to low resistance, the other parent, line 382-48, has a well-known source of resistance, Solanum demissum, in its pedigree. Segregation of late blight disease severity in a population of 95 hybrid plants from cv. Ando’s backcross to cv. Agra (cv. Ando x cv. Agra BC1) in field trials of three consecutive years (2013?2015) and in a test of a single pathogen isolate fits a model of additive action of multiple unlinked race-specific resistance genes responsible for the field resistance of cv. Ando. At least some of the resistance genes in cv. Ando’s genome do not function in juvenile plants and are developmentally upregulated.     

不同生育期水分胁迫对夏玉米叶片光合生理特性的影响

以苏玉20和郑单958为材料,采用盆栽控水试验,设置干旱、水涝和对照3个处理,研究不同水分胁迫条件对两个夏玉米品种关键生育期（拔节期和抽雄期）光合生理特性的影响。结果表明：（1）干旱和水涝均会降低夏玉米的叶片绿色度值（SPAD）、净光合速率（NPn）、蒸腾速率（Tr）和气孔导度（Gs）,增加叶片胞间CO2浓度（Ci）。（2）两个夏玉米品种抽雄期对水分的敏感程度高于拔节期,且对水涝的敏感程度大于干旱。（3）两个夏玉米品种对水分逆境胁迫的抗性相比,苏玉20与郑单958的抗旱性相同,而苏玉20的抗涝性小于郑单958。研究结果可为探明不同种植区夏玉米水分抗逆性研究提供理论依据。     

香菇细胞核的研究

通过对双核期香菇菌丝体２４ｈｒ的观察，我们发现了香菇菌丝细胞核有四个分裂细胞核有四个高峰期：即２：３０－３：３０；８：３０－１０：３０；１６：００－１７：００；２０：３０－３１：３０。其中８：３０－１０：３０为最大的核分裂高峰期，２０：３０－２１：３０为最小的核分裂高峰期，在观察中我们还发现香菇细胞核进行有丝分裂时香菇染色体数是８个。     

运城市主要果树花期冻害指标研究

运城市主要果树近年来均有不同程度花期冻害发生,为减少冻害损失,制定更具生产指导意义的农业气象灾害指标以及农业气象灾害标准,文中以运城市主要种植果树苹果、梨、桃、杏花器官为研究对象,利用智能人工气候箱模拟自然降温进行研究。结果表明:运城市苹果花期、梨花期、杏花期遭受冻害临界温度均为-2℃,桃花期遭受冻害临界温度为-3℃;苹果花期、杏花期遭受重度冻害临界温度均为-4℃,梨花期遭受重度冻害临界温度为-3℃时,桃花期遭受重度冻害临界温度为-6℃;其冻害程度均随温度的降低和持续时间的增加而加重,其中最低温度与低温持续时间是苹果、梨、杏的花期冻害主导指标,最低温度是桃花期主导指标,低温持续时间是桃花期辅助指标。以此建立包含果树花期冻害等级、极端最低气温、低温持续时间、受冻表现共4要素在内的运城市苹果、梨、桃、杏花期冻害指标,并通过实际灾情验证。     

花铃期减量滴灌对北疆棉花光合特性及产量的影响

针对近年来新疆北部(北疆)棉花花铃期降雨量增加的现象,为明确花铃期减量滴灌是否可行及其对棉花产量形成过程的影响,以新陆早50号和新陆早73号为材料,设2个花铃期减量滴灌处理(W_1:2 050 m~3·hm~(-2),W_2:1 650 m~3·hm~(-2)),同时以最适滴灌量作为对照(CK:2 450 m~3·hm~(-2)),系统分析了棉田0～60 cm不同土层土壤含水率动态变化、冠层叶片光合荧光特性和产量构成。结果表明:随滴灌量减少,各土层土壤含水率降幅增加。在处理33～45 d,两个品种减量滴灌处理气孔导度(G_s)、胞间CO_2浓度(C_i)和净光合速率(P_n)分别下降5.40%～35.48%、1.24%～9.47%和9.22%～26.78%,品种间比较新陆早50号降幅较大。两个品种相对可变荧光曲线(ΔV_t)在K点(300μs)出现较大波动,且W_2处理高于W_1处理。W_2处理下新陆早50号和新陆早73号ΔK值分别为0.025和0.0239,W_k值较对照分别增加54.55%和35.14%。两个品种棉花叶片M_o、V_I和V_J均表现为W_2 W_1 CK,ψ_o、φ_(Po)、φ_(Eo)和PI_(ABS,total)均随滴灌量减少而降低,其中,新陆早50号降幅较大。W_1和W_2处理下两个品种单株铃数分别减少1.67%～3.17%和14.29%～15.00%,分别减产6.27%～7.77%和19.28%～21.75%,新陆早50号减产较多。减量滴灌处理使棉花叶片P_n下降的主要原因是气孔限制因素,但未造成北疆棉田花铃期严重水分亏缺。W_1处理下两个品种棉花叶片光合机构的PSⅡ供体侧放氧复合体(OEC)未受到明显伤害,减产较少,可作为北疆棉田花铃期供水不足时的参考滴灌量。品种间比较,新陆早73号更适宜北疆棉田供水不足时种植。     

62份陆地棉种质资源苗期抗旱性综合评价及耐旱种质筛选

研究不同棉花品种（系）苗期对干旱引发渗透胁迫的适应性反应,通过多指标鉴定和综合评价苗期棉花供试品种（系）抗（耐）旱性,分析耐旱材料和干旱敏感材料苗期的植株和根系形态变化,为进一步提高棉花抗（耐）旱育种早代选择提供依据。采用15% PEG 6000营养钵砂培法对62份陆地棉种子进行苗期抗（耐）旱性鉴定筛选,分别测定在胁迫条件下以及对照条件下的棉花苗期植株形态、根部形态、以及生物量等18个抗（耐）旱相关指标,利用因子分析、隶属函数分析和聚类分析等方法对苗期的18项相关指标进行抗（耐）旱性综合评价。结果表明,这18个指标在15% PEG 6000 (-0.4 MPa)胁迫条件下,除根冠比和根全长外其他指标均比对照显著降低,说明棉花苗期生长受PEG 6000的抑制,且根系受抑制程度低于地上部植株。通过对这18个指标的处理相对值进行因子分析,抗（耐)旱指标简化可得到6个主因子,包含根部投影面积、根像素面积、根表面积、根部体积等16个指标,其贡献率分别为35.01%、16.53%、12.46%、8.99%、6.60%、6.31%。利用这16个指标对62份陆地棉新材料进行隶属函数分析和相关性分析,并以平均隶属函数值代表抗（耐）旱性强弱,平均隶属函数值越大,抗(耐)旱性越强,结合品种聚类分析结果选出相对抗旱品系7个、相对耐旱品系4个、敏感品系6个;45份材料介于耐旱与敏感之间的过渡类型。     

Remote Assessment of Wheat Canopies under Various Cultivation Conditions Using Polarized Reflectance

Abstract

The polarization of light reflected from crop canopies gives information on the canopy structure, such as the distribution of leaf inclinations. In order to verify those findings and to put the technique to practical use, we conducted two experiments in wheat fields. In the first experiment, the reflectance and polarized reflectance at 660 nm in the canopies of wheat plants, sown in both narrow and wide rows, and at two levels of topdressing, were measured periodically with a spectropolarimeter. We also probed the leaf orientation geometry of the plants using a 3-D digitizer and a plant canopy analyzer (LAI-2000). In the second experiment, we observed the polarization of light reflected from wheat planted in plots fertilized with basal dressing, and topdressing at the jointing and booting stages. Polarization showed a seasonal change with an upward convex clearly indicating the heading time. This pattern was not found by conventional band reflectance. Using polarization, it was possible to detect the differences in row width and fertilization conditions during the booting stage. The mean leaf inclination angle (MLI) detected with the 3-D digitizer and the mean tip angle (MTA) detected with the LAI-2000 were relatively closely correlated with the polarization than the reflectance at 660 nm and normalized difference vegetation index (NDVI) that was derived from the reflectance at 660 nm and 830 nm. Topdressing at the jointing stage was well detected by polarization obtained at the heading stage. Polarization measurements are useful in practical terms for remote detection of changes in stand geometry induced by cultivation management such as topdressing.