Nitrogen Source and Concentration Affect Growth and Performance of Bedding-Plant Impatiens

ABSTRACT

Impatiens (Impatiens wallerana Hook. f.) is the most important annual bedding plant in the United States, based on wholesale dollar volume. Production of high-quality plants requires optimization of the nutrition regimen during growth, especially the total nitrogen (N) concentration and the ratio of N sources. The objective was to determine the N concentration and the nitrate (NO₃ ^??N):ammonium (NH₄ ⁺?N) ratio of N source that optimized bedding-plant impatiens growth and flower development. Four N concentrations (3.5, 7, 10.5, and 14 mmol N · L^?1) were used in factorial combination with four ratios of NO₃ ^??N:NH₄ ⁺?N (4:0, 3:1, 1:1, and 1:3). Application of treatments was made for 30 d. Then for 10 d only deionized water was applied to reduce salt buildup. Substrate pH was lowest (4.9) with the NH₄ ⁺?N source and electrical conductivity (EC) highest, but never > 2.4 dS m^?1. Nitrogen concentration and N source displayed an interaction for most growth parameters. Shoot fresh and dry weights and flower bud number were maximized at the 1:3 NO₃ ^??N:NH₄ ⁺?N ratio with a N concentration of 10.5 mmol L^?1. However, plant diameter, leaf number, and leaf chlorophyll content responded quadratically to N form ratio, with the 1:1 ratio optimum at a concentration of 10.5 mmol N· L^?1.     

凤仙透骨草中抑菌活性物质提取工艺研究

以意大利青霉做指示菌,以抑菌圈直径为活性追踪指标,在单因素实验的基础上通过二次回归正交旋转组合设计进行凤仙透骨草中抑菌活性物质的提取工艺参数优化。结果表明:最佳提取工艺条件为φ(乙醇)=96.8%,溶剂倍数10倍,提取温度50℃,提取时间3 h,在此优化条件下抑菌圈直径为36.95 mm。各因素对凤仙透骨草提取物抑菌效果的影响由大到小依次为:乙醇浓度,溶剂倍数,提取时间,提取温度。     

睫毛萼凤仙花核型研究

为弄清睫毛萼凤仙花的染色体数目及核型情况,为其系统分类提供细胞学依据,特选取睫毛萼凤仙花的幼嫩根尖作材料,处理制片观察分析其核型。结果表明:睫毛萼凤仙花具14条染色体,核型公式为2 n=2 x=14=14 m,属Stebbins分类中的1A型,较为原始的对称核型。     

铜对新几内亚凤仙生长发育及花色的影响

试验采用砂培的方法,研究了不同浓度的铜对2个品种新几内亚凤仙生长发育及花色的影响。结果表明,新几内亚凤仙红花和紫花品种对不同铜浓度供应的反应不同。当营养液中铜浓度为3.2×10-7mol/L时,2个品种植株体内的可溶性糖含量和花色素苷的含量高且花色深,紫花品种开花数多且花朵直径大;铜浓度为3.2×10-6mol/L时,2个品种植株的根活力和生物量最大,红花品种开花数和花朵直径最大。     

野生天全凤仙叶片光合特性探析

[目地]揭示野生天全凤仙光合作用的基本生理生态学特征和规律,分析其生长的适宜生态条件,为其园林应用提供理论指导。[方法]采用Li-6400便携式光合仪测定野生天全凤仙叶片的有关光合参数,研究了光合作用日变化的特征、影响因子与光合特性之间的关系,以及光补偿点与光饱和点。[结果]野生天全凤仙光合速率日变化呈单峰型,最大光合速率为10.99μmol/（m^2·s）。光合速率与气孔导度之间呈正相关,与胞间CO2浓度呈负相关。叶片光补偿点为13μmol/（m^2·s）,光饱和点为500μmol/（m^2·s）,表观量子效率为0.0549。[结论]野生天全凤仙的光合特性表明其为典型的耐阴植物。     

Computational analysis of mutated AHAS in response to sulfonylurea herbicides

Sulfonylurea (SU) herbicides that target acetohydroxyacid synthase (AHAS, also called acetolactate synthase (ALS)) are regarded as one of the most important classes of herbicides, due to their extremely low toxicity towards mammals, ultra‐low dosage application and high selectivity. However, mutations of AHAS to a herbicide‐insensitive form appear to be a worldwide problem for acquired resistance. In this study, three mutated AHAS sequences were used. In the mutated AHASs, the proline (Pro) was replaced by one of threonine (Thr), alanine (Ala) or serine (Ser) in AHAS amino acid (AA) position 197Pro. To understand the herbicide resistance mechanism, we built dimeric AHAS complex models based on 1YBH of protein data bank (PDB) with SU herbicide, chlorimuron ethyl (CIE), using a homology. The three mutated AHASs in complex with CIE were analysed, and the resistance mechanism to SU herbicides was studied by molecular dynamics (MD) simulation performed using GROMACS 4.5.5. MD simulation analysis of wild‐type and the three mutated dimeric AHAS–CIE complex systems revealed the conformational stability and changes in herbicide binding to dimeric AHAS system due to the mutation. Additionally, it showed that conformational change of amino acid residue 200Met (methionine) was associated with the imidazolinone herbicide resistance mechanism. According to our computation, the detailed mechanism of herbicide resistance was variable, depending on the type of mutated amino acid, providing new insights for designing herbicides specific to each mutant AHAS.     

园林废弃物堆腐产品在花卉基质栽培中的应用研究

【目的】研究由广东地区园林废弃物堆腐产品组成的基质对花卉生长的影响,探讨堆腐产品作为 园林植物栽培基质的可能性。【方法】测定由不同比例堆腐物组成基质的理化性质及其对非洲凤仙和矮牵牛两 种草花生长特性的影响。【结果】园林废弃物堆腐产品组成的基质容重低、总孔隙度高、有机质和氮、磷、钾 元素含量高,其中堆腐物中的有效氮磷钾分别为 686.80、453.20、10 120.90 mg/kg,是较为理想的花卉栽培基质。 堆腐物组成的基质可促进非洲凤仙和矮牵牛根系生长,提高地上部叶片的叶绿素含量,促进叶片生长,并且促 进花枝分蘖,增加植株冠幅和株高,从而提高干鲜质量和开花数。隶属函数法分析发现,最适合非洲凤仙生长 的基质为纯堆腐物组成的基质,函数值为 0.73;最适合矮牵牛生长的基质为市售栽培基质∶堆腐物 7 ∶ 3 的基质, 其函数值达到 0.97。【结论】园林废弃物堆腐产品组成的基质可作为非洲凤仙和矮牵牛两种草花的栽培基质组分。     

纱网袋颜色对红雉凤仙花传粉者不同时间段访花行为的影响

盗蜜对植物生殖成功的影响仍存在争议,通过用纱网袋套蜜距隔离盗蜜者创设无盗蜜者的对照可有效研究盗蜜的生态学后果和机制,但因为传粉昆虫会偏爱某一色系的花朵,纱网袋颜色可能会干扰传粉者行为.为了筛选对传粉者干扰最小的纱网袋颜色,设计了4种颜色(黑、白、红、绿)纱网袋套蜜距,以不套蜜距作为对照,在一天中6个时间段观测红雉凤仙花...     

蜡蚧轮枝菌单孢分离菌株和诱变菌株对甘蓝蚜的室内毒力测定

用蜡蚧轮枝菌KM9803菌株及其单孢分离菌株KM9803A、KM9803F、KM9803G,其紫外线诱变菌株Z2和化学诱变菌株H2对甘蓝蚜进行室内毒力测定,并将6菌株的毒力进行比较。结果表明,KM9803F菌株最强,其LC50值在第4(103),5(101)天都明显小于其他菌株(均在105以上);第6,7天的KM9803F的LC50值仍小于其他菌株,只不过差距缩小;在同一数量级(105,106)下对各菌株的LT50进行比较,都以KM9803F的致死中时间最短,为3~4 d,其余菌株均在4 d以上。     

新几内亚凤仙花瓣发育过程中花色素苷及其相关生化物质含量的研究

为进一步探索花色素苷及其合成过程中某些生化物质含量的关系,将新几内亚凤仙花瓣发育分为8个阶段,通过测定各阶段花瓣中可溶性糖、可溶性蛋白质和脱镁叶绿素的含量以及苯丙氨酸解氨酶活性来探讨上述因素对花色素苷积累的影响。结果表明:花瓣发育过程中,花色素苷含量在花蕾即将开放时达到最高值;花色素苷合成的关键时期在花瓣发育的前4个阶段;可溶性糖、可溶性蛋白质和叶绿素含量以及苯丙氨酸解氨酶活性与花色素苷的累积均有一定相关性;花未开放之前,随着花色素苷含量的增加,可溶性糖含量增加,而可溶性蛋白质含量下降;苯丙氨酸解氨酶在花瓣发育前期表现出较高活性,其峰值均先于花色素苷的峰值出现;脱镁叶绿素的降解有助于花色素苷的合成。