苗后除草剂喷施时期对杂草防治及冬油菜产量和品质的影响

为了探究苗后除草剂不同施用时期对北方冬油菜田间杂草的防控效果及其对冬油菜生长、产量和品质的影响,以当地主栽甘蓝型冬油菜天油2266和白菜型冬油菜天油H614为试验材料,选用对冬油菜安全的苗后除草剂高效氟吡甲禾灵,设置4个喷施时期处理,于2018-2019年开展大田试验。结果表明,越冬后不同时期喷施苗后除草剂,甘蓝型冬油菜田间杂草总数较对照减少57.54%~92.56%,杂草总鲜重较对照降低75.40%~97.48%,第2时期（3月25日）处理产量较对照增加354.50kg/hm²;白菜型冬油菜田间杂草株防效和鲜重防效分别为55.91%~92.02%和37.17%~97.46%,产量较对照增加2.29%~16.77%。因此,在冬油菜大量返青但未封行前施用苗后除草剂,可显著防控田间杂草并增加冬油菜籽粒产量。     

PEG胁迫下春小麦萌发期抗旱指标的遗传力

为探索干旱胁迫对春小麦萌发期生长的影响,筛选春小麦萌发期抗旱性指标。以宁夏灌区和雨养区的2种粒色（红皮和白皮）40份春小麦的抗旱品系为试验材料,研究PEG-6000模拟干旱胁迫对胚根长、胚根数、胚芽鞘长和一叶长的影响。利用广义遗传力分析法,筛选春小麦萌发期抗旱性指标。胚根长的广义遗传力最高,均大于0.55,遗传力的控制程度稳定。雨养区的红粒种子胚根长的遗传力高达0.95;雨养区的红粒种子的胚芽鞘长的广义遗传力最高,达0.94,但其遗传力控制程度不稳定,最低遗传力仅为0.06;胚根数和一叶长的遗传力很低,且控制程度极不稳定。春小麦萌发期胚根长的广义遗传力最高,控制程度稳定。其次是胚芽鞘长,但其遗传力的控制程度不稳定。胚根长可作为春小麦萌发期的抗旱指标鉴定抗旱材料,以胚芽鞘的长度为参考值。     

安康市核桃果实害虫种类调查研究

采用生长期定点定株定期果实害虫调查和贮藏期室内常温贮藏观测法,对安康市核桃果实害虫种类进行了调查。结果为安康市核桃果实生长期害虫有13种,隶属5目11科;核桃果实贮藏期害虫有3种,隶属2目3科;核桃生长期危害较大的果实害虫主要是核桃举肢蛾、核桃长足象、双鬃尖尾蝇和桃蛀螟;贮藏期危害较大的果实害虫是印度谷螟;首次发现并记录了角斑古毒蛾幼虫为害核桃幼果。     

Seasonal Changes in the Milt Quality of Waigieu Seaperch,Psammoperca waigiensis: Implications for Artificial Propagation

Milt quality of Waigieu seaperch was sampled at the beginning, the middle, and the end of the spawning season to assess if the sampling season has an effect on milt quality parameters. The milt volume and total sperm production were higher at the middle of the spawning season while the sperm concentration in milt was significantly higher at the beginning and the end of the spawning season. Sperm morphology and the major parameters of seminal plasma (pH, total protein, Mg²⁺, or Ca²⁺ concentrations) did not differ throughout the spawning season. The concentrations of Na⁺ and the osmolality increased throughout the spawning season. The percentage of motile cells did not differ during the spawning season while the duration of sperm motility (swimming duration) and velocity (swimming speed) were significantly different during the spawning season. The fertilization rate (75.7 ± 6.8%) and hatching rate (56.5 ± 3.1%) at the middle of the spawning season were higher than at the beginning and end periods. Results indicated that milt quality parameters and fertility success in the middle of the spawning season were higher compared to earlier and later sampling dates. Thus, we recommend collecting milt during this time for maximal fertilization and hatching success.     

Characterization and bioactivities of young rice protein hydrolysates

Immature rice was reported to contain higher quantities of bioactive compounds than mature rice. Young rice protein is easy to digest and has hypoallergenic potential, with protein content of 7.2–11.5% compared to rice bran at 9.8%. Few studies have reported on bioactivities and characterization of young rice proteins and their hydrolysates. Bioactivities of native protein and protein hydrolysates of two rice varieties (white rice and colored rice) were characterized and investigated for four development stages (flowery, milky, dough, and mature). Degree of hydrolysis of young rice protein was considerably higher than at the mature stage. Highest DPPH and iron chelating activity were found in alcalase® protein hydrolysate during the flowery-to-milky stage. Iron chelating activity was constant in all development stages because of the low polar amino acid content in rice. The ACE activity of alcalase® protein hydrolysate was higher than native protein at the same development stage, as observed in the milky and dough stages. Inhibitory activity of young rice hydrolysate HepG2 cells was concentration-dependent and not correlated with protein molecular size.     

苗期甘蔗氮高效基因型评价指标的筛选

本研究通过低氮压力选择,筛选出甘蔗氮高效种质,分析影响甘蔗氮高效的重要指标,为甘蔗氮高效育种及栽培提供理论依据。以58份甘蔗种质资源为材料,在苗期采用正常供氮（2 mmol/L N）和低氮（0.2 mmol/L N）处理,分析甘蔗植株形态、干重及氮素在各器官中累积分配的特征。通过主成分分析方法筛选影响甘蔗氮高效利用的重要指标,通过聚类分析对58份种质进行聚类。结果表明,低氮（0.2 mmol/L N）处理可以明显从植物形态区分不同种质的氮利用差异,58份种质低氮条件下的干重范围为0.64~14.75 g/株,氮累积量为5.53~63.00 mg/株,氮利用率范围为115.40~279.30 g/g。对低氮压力下甘蔗干重及氮累积等25个指标进行主成分分析后,提取出4个主要成分,总贡献率为92.35%。通过高、低氮条件下与氮利用效率有关的氮转移系数及基因潜力等19个指标分析后提取出5个主成分,总贡献率为82.21%。影响甘蔗氮高效的重要指标有甘蔗的干重（全株、叶、根）、氮累积量（全株、叶、茎）、氮利用率（全株、叶）、叶的相对氮利用率、茎的基因潜力、茎的相对干物质量和茎的相对氮累积量。经聚类分析后初步将58份甘蔗种质分为氮高效基因型、偏氮高效基因型、偏氮低效基因型和氮低效基因型。     

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。     

痕量灌溉对棉花花铃期光合性能日变化及产量的影响

【目的】明确痕量灌溉方式在干旱区灌溉棉田的适用性。【方法】本研究以中棉所92为供试材料,系统监测了痕量灌溉不同埋管深度30 cm(D30)、40 cm(D40)和50 cm(D50)和膜下滴灌(CK)4个处理的棉花花铃期光合日变化及产量效应。【结果】①不同处理下净光合速率和气孔导度的日变化均呈双峰曲线变化趋势,且D30处理各时段的净光合速率和气孔导度均高于其他处理。②不同处理下的胞间CO2摩尔分数日变化均呈广口"V"字形双峰曲线变化趋势,蒸腾速率日变化均呈单峰曲线变化趋势,最大值出现在14:00h。③D30处理的2年平均籽棉产量和平均皮棉产量最高,分别为5 734.28和2 454.53 kg/hm^2,其中籽棉产量分别比CK、D40和D50处理高出1.09%、7.63%和11.38%,皮棉产量分别比CK、D40和D50处理高出3.49%、8.32%和1.61%。【结论】综合光合性能日变化和产量分析得出,内蒙古阿拉善地区采用埋管深度为30 cm的痕量灌溉技术为最佳。     

Thresholds,sensitive stages and genetic variability of finger millet to high temperature stress

Finger millet [Eleusine coracana (L.) Gaertn.] is an important coarse cereal crop grown in the arid and semi‐arid regions and often experiences high temperature (HT) stress. The objectives of this research were (i) to quantify effects of season‐long HT stress on physiological and yield traits, (ii) to identify the developmental stages most sensitive to HT stress and (iii) to quantify the genetic variability for HT stress tolerance in finger millet. Research was conducted in controlled environment conditions. HT stress decreased the chlorophyll index, photosystem II activity, grain yield and harvest index. Maximum decrease in number of seeds per panicle and grain yield per plant was observed when stress was imposed during booting, panicle emergence or flowering stages. Maximum genotypic variation was explained by panicle width and number of seeds per panicle at optimum temperature (OT) and grain yield per plant at HT and number of seeds at HT. Based on the stress response and grain yield, tolerant or susceptible genotypes were identified. Finger millet is sensitive to HT stress during reproductive stages, and there was genotypic variability among the finger millet genotypes for number of seeds per panicle and grain yield under HT, which can be exploited to enhance stress tolerance.     

Carbohydrate and crude protein fractions in perennial ryegrass as affected by defoliation frequency and nitrogen application rate

The objective of this study was to evaluate the effects of defoliation frequency (either at two‐ or three‐leaf stage) and nitrogen (N) application rate (0, 75, 150, 300, 450 kg N ha^?1 year^?1) on herbage carbohydrate and crude protein (CP) fractions, and the water‐soluble carbohydrate‐to‐protein ratio (WSC:CP) in perennial ryegrass swards. Crude protein fractions were analysed according to the Cornell carbohydrate and protein system. Carbohydrate fractions were analysed by ultra‐high‐performance liquid chromatography. Sward defoliation at two‐leaf stage increased the total CP, reduced the buffer‐soluble CP fractions and decreased carbohydrate fractions of herbage (P < 0·001). The effect of defoliation frequency was less marked during early spring and autumn (P < 0·001) than for the rest of the seasons. An increase in N application rate was negatively associated with WSC, fructans and neutral detergent fibre (P < 0·001), and positively associated with CP and nitrate (N‐NO₃) contents of herbage. Nitrogen application rate did not affect CP fractions of herbage (P > 0·05). The fluctuations in CP and WSC contents of herbage resulted in lower WSC:CP ratios during early spring and autumn (0·45:1 and 0·75:1 respectively) than in late spring (1·11:1). The herbage WSC:CP ratio was greater (P < 0·001) at the three‐leaf than the two‐leaf defoliation stage and declined as the N application increased in all seasons (P < 0·001). The results of this study indicate that CP and carbohydrate fractions of herbage can be manipulated by sward defoliation frequency and N application rate. The magnitude of these effects, however, may vary with the season.