Effects of nitrogen and water stress on the rehydration,endogenous hormonal regulation and yield of maize

Water scarcity is known to be a strong limiting factor affecting maize grown and yield in cold semi-arid regions. Numerous studies have shown that rehydration improves maize growth. Our study aimed to explore the effects of rehydration treatments on maize growth and yield under water and nitrogen stress during different growth stages. We selected the drought-tolerant maize variety Nendan 19 (ND19) and subjected it to water stress during the V6 (sixth-leaf), R2 (filling) and R6 (maturity) growth stages and a rehydration treatment after each stress stage. Our results indicated that N1 (N100 kg N ha⁻¹) and N3 (N300 kg N ha⁻¹) treatments significantly increased the leaf moisture status relative to water content (RWC), bound water content (BWC), free water content (FWC) and water potential (WP)) at different growth stages. Similar trends were observed in the accumulation of plant leaf and root hormones (zeatin+zeatin riboside, indole-3-acetic acid, abscisic acid and gibberellic acid), photosynthetic pigments and chlorophyll fluorescence. However, under the same water stress conditions, they decreased as the N rate increased and reached a minimum value in the S3 (water stress for N3) treatments. In addition, with growth stage advancement and extension of the rehydration time, both showed a gradual upward trend. The results showed that to save water resources in the cold semi-arid region, rehydration treatments (R2S1 and R2S3) significantly increased the photosynthetic pigments and chlorophyll fluorescence parameters, leaf moisture status, biomass, 100-grain weight, hormone content, ear characteristics and grain yield of maize.     

烤烟总氮含量和氮碱比与物理性状的关系分析

试验以我国主产烟区的主栽烤烟品种K326为材料,测定X2F(下橘二)等级共计124份样品的总氮、烟碱含量和物理性状,系统地分析总氮含量、氮碱比与物理性状的相互关系。结果表明,总氮含量、氮碱比和物理性状在样品间存在着广泛的变异。总氮含量随单叶重、叶长、叶面密度的增加而逐步下降;氮碱比随叶长、叶宽的增加而上升,随叶面密度的增加而逐渐下降。总氮与叶长、叶面密度的关系可分别用逆函数■=0.827 38.047/x、复合函数■=1.880×0.996x描述;氮碱比与叶宽、叶面密度的关系可分别用复合函数■=0.413×1.023x描述、幂函数描述■=2.791x-0.354。     

Forest biomass and root–shoot allocation in northeast China

Temperate and boreal forests act as major sinks for atmospheric CO₂. To assess the magnitude and distribution of the sinks more precisely, an accurate estimation of forest biomass is required. However, the determinants of large-scale biomass pattern (especially root biomass) are still poorly understood for these forests in China. In this study, we used 515 field measurements of biomass across the northeast part of China, to examine factors affecting large-scale biomass pattern and root–shoot biomass allocation. Our results showed that, Picea & Abies forest and coniferous & broadleaf mixed forest had the highest mean biomass (178–202 Mg/ha), while Pinus sylvestris forest the lowest (78 Mg/ha). The root:shoot (R/S) biomass ratio ranged between 0.09 and 0.67 in northeast China, with an average of 0.27. Forest origin (primary/secondary/planted forest) explained 31–37% of variation in biomass (total, shoot and root), while climate explained only 8–15%, reflecting the strong effect of disturbance on forest biomass. Compared with shoot biomass, root biomass was less limited by precipitation as a result of biomass allocation change. R/S ratio was negatively related to water availability, shoot biomass, stand age, height and volume, suggesting significant effects of climate and ontogeny on biomass allocation. Root–shoot biomass relationships also differed significantly between natural and planted forests, and between broadleaf and coniferous forests. Shoot biomass, climate and forest origin were the most important predictors for root biomass, and together explained 83% of the variation. This model provided a better way for estimating root biomass than the R/S ratio method, which predicted root biomass with a R² of 0.71.     

60%吡唑醚菌酯·代森联水分散粒剂防治猕猴桃褐斑病田间药效试验

2017年开展的60%吡唑醚菌酯·代森联水分散粒剂防治猕猴桃褐斑病田间药效试验,结果表明,该药剂对猕猴桃灰霉病有很好的防治效果,于叶片发病初期使用有效剂量400~600mg/kg,连续茎叶喷雾2次,10d后防治效果达75%~83%,试验剂量下对猕猴桃树生长安全。     

汞镉对游离和固定化脲酶活性的影响

通过对脲酶与汞镉间关系的研究 ,结果表明 :不同状态 (溶液态、粘粒态和土壤态 )脲酶对汞、镉的反应表现出类似的规律性变化 ,即汞、镉抑制脲酶活性 ,其中汞镉复合污染的影响幅度最大 ,汞的生态毒性最强 ;相关分析显示脲酶活性均可表征样品汞、汞镉污染的程度 ;在汞、镉共存条件下 ,脲酶活性不仅受到汞、镉单因素 ,而且受到它们间交互作用的影响 ,但仍以单独抑制为主 ;由于不同状态脲酶载体的差别 ,导致受影响幅度有较大差异 ,其主要取决于载体对脲酶保护作用和重金属缓冲作用的大小 ,溶液态脲酶无载体 ,而粘粒态和土壤态则相反 ,故溶液态脲酶更易受到重金属的破坏 ,酶的反应也较敏感。温度和尿素浓度均增强了汞镉的抑制作用     

黑龙江省谷糜病毒病的鉴定

试验证明 ,谷糜病毒病毒原的传毒介体为灰飞虱 (L aodel phax striatella Fallen) ,不能经卵传毒 ,生物学测定及田间调查表明 ,该病毒病的症状在谷糜上略有不同 ,二者均表现为矮化、丛生、花叶、后期叶片变红 ,这与小麦丛矮病显著不同 ;谷子还表现硬穗症状。寄主范围与小麦丛矮病一致。EL ISA及免疫电镜测定结果表明 ,该病毒与小麦丛矮病的抗血清呈阳性反应 ,结果证实该病毒为小麦丛矮病毒 (WRSV) ,又称北方禾谷花叶病毒 (NCMV)。     

农产品加工业与农业产业化

发展农产品加工业是实现农业产业化的前提和基础,阐述我国农产品加工业现状、存在问题,以及农产品加工业在农业产业化进程中的作用,并提出农产品加工业未来的发展目标。     

养殖中华绒鳌蟹风味品质比较研究

通过对江苏太湖、阳澄湖、滆湖、长荡湖、固城湖、洪泽湖、高宝湖、大纵湖八大养殖品牌河蟹测试分析,结果表明：平均体重120-200g的商品蟹,可食部分总指数〉30%,最高的太湖蟹达35.71%,最低的滆湖蟹为30.01%,各品牌河蟹之间差异不显著（p〉0.05）。肥满度以滆湖蟹最高,阳澄湖蟹最低,各品牌河蟹之间差异不显著（p〉0.05）。固城湖蟹的粗蛋白含量显著高于阳澄湖蟹（p〈0.05）,虽高于其它品牌河蟹,但差异不显著（p〉0.05）。可食部分17种氨基酸总量依次为：17.48、15.90、17.31、18.21、19.42、16.62、17.85、17.25;固城湖蟹与阳澄湖蟹的差异达极显著水平（p〈0.01）,与洪泽湖蟹的差异达显著水平（p〈0.05）,长荡湖蟹与阳澄湖蟹的差异达显著水平（p〈0.05）,其它品牌河蟹之间的差异不显著（p〉0.05）。固城湖蟹鲜味氨基酸含量显著高于阳澄湖蟹（p〈0.05）,其它品牌河蟹差异不显著（p〉0.05）。必需氨基酸指数依次为：77.29,75.80,83.12,78.73,77.33,70.55,75.91,73.93。必需氨基酸含量分别占总氨基酸的47.99%、47.80%、48.01%、43.95%、47.35%、48.23%、47.81%、49.47%,低于全鸡蛋白质模式,但均明显高于FAO/WHO模式。     

2012/2013渔季CAMLR 48区南极磷虾(Euphausia superba)资源时空分布

根据2013年1–9月辽宁远洋渔业有限公司“福荣海”轮南极磷虾拖网调查数据,以3n mile/h拖曳获得的产量作为CPUE指标,对南极磷虾资源时空分布进行了分析。结果显示,1–6月的月均CPUE值相对稳定,7–9月逐月下降。各渔区中平均CPUE值以48.1区最高,为(25.12±31.04) t/h;48.3区最低,为(11.49±12.06) t/h;CPUE值的波动幅度48.1区大于48.2和48.3区。48.1区的南极磷虾群主要分布于0 –100 m水层,CPUE值以25–50 m水层为最高;48.2区虾群主要分布于50–150 m水层,CPUE值以100–150 m水层最高;48.3区虾群主要分布于100–250 m水层,CPUE值以200– 250 m水层最高。海底深度<500 m的近岸海域是磷虾主要集群分布区和商业捕捞渔场,以水深<250 m的浅水区渔场虾群密度最大,平均CPUE值为(17.54±35.26) t/h,水深250–1500 m的深水区渔场平均CPUE值变化较小,在12.0–14.0 t/h之间波动,但水深>1500 m时,平均CPUE值降到(9.62±9.54) t/h。作业渔场的表温SST主要集中在－1–2℃,当SST为－1–0℃时,平均CPUE值最高。探捕调查发现了5个主要的磷虾集群,集群时间可达30 d以上,但集群密度随时间发生变化。调查结果可为研究南极磷虾渔场形成机制和渔业管理提供基础数据,并为商业捕捞提供参考。