Influence of boron on seed yield and seed quality of organic white clover (Trifolium repens L.)

The effects of boron (B) application on flower development, nectar production, germination and seed yield were investigated in organic seed crops of white clover grown in soils with <1 mg B kg^?1. Application techniques of a liquid B product were studied in two field experiments in 2009–2011. Three rates of B application to the soil at sowing and three rates of B as a foliar application in the harvest year were compared with untreated control plots. None of the B treatments had a significant effect on seed yield, relative to the control. In one experiment, with a dense crop stand, the results indicated a small (10%) yield increase with B applied to the soil. Seed germination and B concentration of shoots, roots and seeds were unaffected by B application, although the soil concentration increased. In seeds with an average B concentration of 22 mg kg^?1, 73% germinated as normal seedlings and 14% were assessed as hard seeds; corresponding values for seeds with an average B concentration of 17 mg kg^?1 were 60 and 38% respectively. The results indicate the need for further studies of factors determining B uptake in white clover .     

盐胁迫对白三叶种子萌发及幼苗生理特性的影响

采用0.00%、0.20%、0.40%、0.60%、0.80%4个浓度的NaCl胁迫白三叶种子,通过种子萌发特性和生理特性的变化,研究其种子萌发、幼苗生长和生理特性。试验结果表明:盐胁迫对白三叶种子的发芽率、发芽势产生显著的影响;当NaCl浓度0.40%时白三叶幼苗和根的生长速度几乎不受影响,≥0.40%时受到抑制;白三叶幼苗体内游离脯氨酸、MDA和可溶性糖含量与盐度的上升呈正相关关系。     

NaCl胁迫对三叶草种子耐盐性的评价

以新疆三叶草(08-2)、瑞文德和海法3个三叶草品系为材料,以NaCl为胁迫因子,设置0,0.1%,0.2%,0.3%,0.4%,0.5%和0.6%共7个盐浓度梯度,研究盐胁迫对三叶草的发芽率、根长、脯氨酸、丙二醛和电导率等生理生化指标的影响.试验结果表明,新疆三叶草08-2的半致死发芽率是0.6%,瑞文德和海法的依次...     

喀斯特地区永久性禾草╋白三叶混播草地群落种间竞争与共存

永久性混播草地群落中,豆科牧草与禾草之间竞争不对等而实现竞争共存。在贵州灼圃示范牧场采用白三叶(Trifolium repens)分别与紫羊茅(Festuca rubra)、鸭茅(Dactylis glomerata)分两组建植并持续适度利用20年后的混播草地开展的去除试验表明,去除伴生禾草后,白三叶生物量、盖度和密度增加,禾草对白三叶有竞争关系,竞争强度随季节而不同,生长季节开始时小,后期增大。去除白三叶后初期,禾草产量变化不大,随后下降,白三叶对紫羊茅和鸭茅的竞争系数基本上为负数,范围在-0.023～-0.394,表明禾草由于依赖白三叶的固氮作用而形成的偏利关系大于白三叶对禾草的竞争影响。在适度放牧混播草地系统中,豆科、禾草之间的不对称竞争是白三叶长期维持合理比例和混播组分之间动态平衡的重要机制。     

南迪诺白三叶营养需求沙培试验的初步研究

以沙为栽培基质,南迪诺白三叶为指示植物,开展了氮、磷、钾、钙、镁、硫、铜、锌、锰、硼、铁、钼十二种必需元素肥的沙培肥效试验。结果表明,南迪诺白三叶对氮、磷、钾、锌、镁的缺乏较敏感,其次为硼,对钙、硫、铜、锰、铁、钼的施用不敏感,所以在单一地种植南迪诺白三叶时,除了考虑土壤的肥力和各种矿质元素含量,一定要重视磷、钾、锌、镁、氮肥的供给,其次为硼肥,可不考虑硫、铜、锰、钼元素肥的施用。     

镉胁迫对白三叶和马蹄金种子萌发的影响

采用不同浓度的镉处理白三叶和马蹄金种子,研究两者萌发阶段对镉胁迫的反应。结果表明：镉浓度低于5mg／L时促进了白三叶和马蹄金种子的萌发。镉浓度为10mg／L时,白三叶发芽率和活力指数开始下降,而马蹄金依然高于对照。随镉处理浓度的继续增高,两者种子发芽率和活力指数逐渐下降。两个草种相比较,在相同镉胁迫作用下,马蹄金比白三叶表现出了较强的耐镉性。     

野生马蹄金花粉生活力检测方法比较

以野生马蹄金(Dichondra repens)材料SD200303和GD200503为对象,分别以碘 碘化钾染色法、联苯胺 甲萘酚染色法、TTC法和离体萌发法测定其花粉活力,比较各检测方法测定效果。结果表明,碘 碘化钾染色法、TTC法染色效果不佳,不适宜野生马蹄金花粉活力测定;联苯胺 甲萘酚染色法能测定花粉生活力,但测定值偏高;离体萌发法测定野生马蹄金花粉活力,花粉管生长良好,且萌发率基本稳定,便于快速直观统计花粉生活力,适宜野生马蹄金花粉生活力检测,其较适宜的培养基为蔗糖10%＋硼酸(HBO3)0.005%＋硝酸钙 [Ca(NO3)2·4H2O] 0.015%＋硫酸镁(MgSO4·7H2O)0.001%＋硝酸钾(KNO3)0.005%＋0.5%琼脂。     

Autochthonous Dirofilaria (Nochtiella) repens infection in dogs in Kuwait

Human dirofilariasis caused by Dirofilaria repens is a rare but increasingly reported zoonosis in the Middle East. However, eligible animal reservoirs seldom have been investigated in the area until now. Seven (1.8 percent) out of 381 dogs examined in Kuwait carried D. repens microfilariae showing compatible cutaneous clinical signs and positive response to the adulticide and microfilaricide therapies. This study indicates that dogs from Kuwait are natural hosts of D. repens and therefore act as an animal reservoir for the zoonotic condition.     

基于SSR分子标记的13个白三叶(Trifolium repens L.)品种指纹图谱构建

白三叶(Trifolium repens L.)是一种多年生冷季型豆科牧草,因其具有产量高、品质优良等特点,已成为我国西南地区重要的优质牧草.为分析国外引进的白三叶新品种的遗传多样性,本研究利用简单重复序列(Simple sequence repeats,SSR)分子标记对13个白三叶品种进行品种鉴定及DNA指纹图谱的...     

水龙在不同富营养水体中光合特性的变化

对水龙在不同富营养水体中生长时的光合生理生态特征变化进行了测定。结果表明,水龙可以在一定的富营养水平下正常生长,光合速率及表观量子产额表现为上升的趋势,叶绿素含量也相应增加;但在超富营养条件下,水龙植株的生长受到抑制,光合速率及呼吸速率均呈现出显著的下降趋势,气孔导度表现为上升的趋势,表观量子产额呈下降趋势,叶绿素含量尤其是叶绿素a含量受到显著影响;培养至38 d后,植株全部死亡。