紫云英结荚翻耕还田对土壤肥力及水稻产量的影响

利用田间小区试验研究了紫云英盛花后不同时期翻耕的干物质量和植株含氮量关系,及比较结荚期不同翻耕量对稻田土壤和水稻产量的影响。结果表明：从盛花期至结荚成熟期紫云英氮素含量逐渐降低,盛花期后鲜产量也逐渐降低,而对应单位面积干物重在盛花期后则呈现上升趋势。采用紫云英结荚成熟期翻耕技术,氮素虽比盛花期还田有一定损失,但与单季稻茬口衔接,可减少翻耕成本、节省播种种子及用工成本;结荚期紫云英翻耕能提高稻田有机质含量,实现增产效果。     

Distribution and reproduction of the planktonic copepod, Calanus pacificus, off southern California during winter-spring of 1992, relative to 1989–91

Abundance and production of eggs by female Calanus pacificus off southern California were assessed in February and April, 1992, together with biomass of chlorophyll and abundance of larval anchovy. Because 1992 was an anomalous year as a result of a Californian El Nino, the patterns were compared with analogous data for 1989-91. Female Calanus were much less abundant in both February and April of 1992 than in the earlier years, and the anomalies were negatively related to temperature anomalies, but the biomass of chlorophyll and per capita egg production were anomalously low only in February. The horizontal distribution of female Caianus was similar to that of chlorophyll in winter, but was more efficient (in the sense of permitting more complete utilization of the available chlorophyll) in April, 1992, than in the earlier springs. The abundances of larval anchovy were positively correlated with the reproduction of the Calanus population in 1992 and in the earlier years, but the larvae were poorly distributed with respect to Calanus spawning, in both 1992 and the earlier years, to take best advantage of the resulting nauplii as food.     

紫云英绿肥对土壤养分的影响

采用盆栽试验,通过对紫云英翻压后不同时期的水稻播秧和不播秧土壤样品进行测定,研究了紫云英翻压后土壤养分的变化规律.结果表明:紫云英翻压第1年能提高土壤中速效氮、速效磷、速效钾含量、增加土壤有机质含量,但增加幅度不大.水稻生长前期紫云英腐熟,养分没有释放出来,所以翻压紫云英田块前期应该施足氮肥,水稻进入旺盛生长期仅仅依靠...     

施用氮磷钾肥对紫云英生长·产量的影响

[目的]研究不同肥料运筹措施对紫云英生长的影响和增产效果。[方法]通过田间试验,研究氮磷钾肥配合施用对紫云英根瘤数量、鲜草和籽粒产量的影响。[结果]氮磷钾肥对紫云英根瘤数量的影响顺序均为P〉K〉N。初花期氮磷钾配合施用处理紫云英鲜草产量最高,而盛花期为NP处理最高,氮磷钾肥对鲜草的增产效果为P〉K〉N。氮磷钾肥对紫云英籽粒产量的影响大小顺序为P〉K〉N。[结论]增施磷肥是提高紫云英鲜草和籽粒产量的关键。氮肥、钾肥后移对紫云英籽粒产量提高也有一定的作用。     

紫云英还田对常规红米水稻产量和品质的影响

为探明紫云英作绿肥对常规红米水稻品种产量和主要品质指标的影响,以常规地方品种小白占和高原红为材料,于2014-2015年在贵州盘县进行紫云英还田4个不同肥料处理(T1,紫云英全量还田;T2,全化学氮肥;T3,紫云英全量作底肥、追施40%化学氮肥;CK,不施肥)的田间试验。结果表明,紫云英全量还田的处理比未施肥对照显著增产,2个品种T1、T2和T3处理的产量分别比对照提高17.5%、45.5%、41.4%和12.6%、28.4%、23.7%,增产的原因主要得益于有效穗数和每穗粒数的显著增加。紫云英全量还田能优化水稻群体结构,提高成穗率,改善收获指数,降低株高而减小倒伏风险;紫云英全量还田能减少化肥的使用,与T2处理相比,T3处理可减少60%的化学氮肥;紫云英全量还田还能显著增加整精米率、降低垩白粒率、提高胶稠度。紫云英全量还田技术在贵州山区常规稻优质安全种植上具有良好的应用效果。     

Effect of Grazing-Mediated Dimethyl Sulfide (DMS) Production on the Swimming Behavior of the Copepod Calanus helgolandicus

Chemical interactions play a fundamental role in the ecology of marine foodwebs. Dimethyl sulfide (DMS) is a ubiquitous marine trace gas that acts as a bioactive compound by eliciting foraging behavior in a range of marine taxa including the copepod Temora longicornis. Production of DMS can rapidly increase following microzooplankton grazing on phytoplankton. Here, we investigated whether grazing-induced DMS elicits an increase in foraging behavior in the copepod Calanus helgolandicus. We developed a semi-automated method to quantify the effect of grazing-mediated DMS on the proportion of the time budget tethered females allocate towards slow swimming, typically associated with feeding. The pooled data showed no differences in the proportion of the 25 min time budget allocated towards slow swimming between high (23.6 ± 9.74%) and low (29.1 ± 18.33%) DMS treatments. However, there was a high degree of variability between behavioral responses of individual copepods. We discuss the need for more detailed species-specific studies of individual level responses of copepods to chemical signals at different spatial scales to improve our understanding of chemical interactions between copepods and their prey.     

紫云英不同翻压时间对土壤养分含量及晚稻养分吸收的影响

在大田条件下,研究了在早稻移栽前,紫云英不同翻压时间对晚稻收获后土壤养分含量以及晚稻养分吸收的影响。结果表明:在早稻移栽前5~15 d翻压紫云英均有利于提高土壤中全N含量以及有效N、P和K含量,但是对土壤中全P、全K含量影响不显著。在移栽前5 d翻压紫云英,晚稻茎秆和籽粒中N、P含量和晚稻产量有所下降;在移栽前10~15 d翻压紫云英,可以显著增加茎秆和籽粒中N、P、K含量,并提高晚稻产量,以在移栽前15 d翻压紫云英的效果最好。     

紫云英2个转脂蛋白基因在共生及重金属镉胁迫条件下的表达特征

采用实时荧光定量PCR技术,研究了紫云英共生表达的非特异性转脂蛋白编码基冈AsE246和AsJB259在根瘤发育和固氮过程中的组织和时空表达特征,并初步考察了其在重金属镉胁迫条件下表达水平的变化.结果表明:2个目标基因仪在紫云英根瘤中特异表达,并且均在接种华癸中慢生根瘤菌7653R后22 d左右表达量达到最高.在低浓度...     

仙桃市紫云英-早稻肥效研究

[目的]通过开展紫云英一早稻肥效试验,合理确定在早稻作物上施用紫云英后化肥减量水平,为指导仙桃市早稻科学施肥提供依据。[方法]在早稻田设置紫云英一早稻肥效试验,分析各处理间土壤肥力变动情况和产量差异水平,科学建立施用紫云英后早稻施肥指标。[结果]在早稻田施用紫云英,可以降低土壤pH和容重,提升土壤速效氮磷钾和有机质含量,提高早稻的养分利用率和经济效益。[结论]在早稻施用紫云英后,以减施20％的化肥效果最好、最佳经济施用量为N115．2kg／hm^2．P2O570．8kg／hm^2．K2O98kg／hm^2。     

巨龙竹营养器官解剖学研究

对巨龙竹根、茎、叶等营养器官的显微结构进行了解剖学研究,对其竹笋发育中各细胞的形态特征进行了观察与分析,结果发现：巨龙竹茎的顶端结构为原套—原体结构(原套为1层细胞),在旺盛发育的幼茎的节和节间细胞中,有丰富的淀粉粒;秆茎的节间维管束为断腰型和双断腰型,节部维管束的木质部导管与韧皮部筛管的排列均无规律,并具有多层密集的细胞组成的“韧皮部结”;叶肉细胞包括指状内摺的臂细胞、不规则细胞及放射状细胞,并在维管束两侧具有无色透明的大型梭形细胞,其中脉的维管束往往与许多小维管束交织在一起形成一个复合的维管系统;根的顶端原始细胞为圆锥状排列的原始细胞群,未见典型的组织原分区。