纽荷尔和清家脐橙果实大量元素含量与累积变化

以30年生枳砧清家脐橙和纽荷尔脐橙为材料，分析果实生长发育过程中N、P、K、Ca、Mg、和S 6种大量营养元素含量和累积量变化。结果表明，果实生长发育过程中，纽荷尔和清家果实中N、P、Mg和S含量4月最高，Ca在10月最高，纽荷尔和清家K含量分别在9月和7月最高；纽荷尔果实的N、P、K、Mg和S主要累积时期为7～9月，Ca主要累积时期为9～10月；清家果实的N、P、K、Mg和S主要累积时期为6～8月，Ca主要累积时期为8～10月。清家脐橙果实中大量营养元素的主要累积时期比纽荷尔脐橙早1个月左右。     

不同林龄的四川桤木人工林生态系统中养分的积累

通过对5年生、8年生、14年生的四川桤木人工林生态系统中的乔木层、活地被物层、枯枝落叶层的养分积累的研究表明：随着林分生态系统中年龄的增长，林分各种养分元素的积累总量增加，各层次中大量元素的积累总量也增加；各种大量元素的积累总量都是：N〉Ca〉K〉Mg〉P；各种微量元素的积累总量都是：Fe〉Mn〉Zn〉Cu〉Pb〉Ni〉Cd。     

纽荷尔和清家脐橙果实大量矿质营养元素含量与累积变化

在重庆北碚,以30年生枳砧清家脐橙和纽荷尔脐橙为材料,分析果实生长发育过程中N、P、K、Ca、Mg和S等6种大量营养元素含量和累积量变化。结果表明,果实生长发育过程中,纽荷尔和清家果实中N、P、Mg和S含量4月最高,Ca在10月最高,纽荷尔和清家K含量分别在9月和7月最高;Ca的主要累积时期,纽荷尔脐橙果实为6—7月和9—10月,清家脐橙果实为6月、8月和10月;除Ca外的其他大量矿质营养元素累积量较大的时期,纽荷尔和清家脐橙果实的总体上均为6—9月和11月,但清家脐橙累积最高峰一致出现在6月,纽荷尔脐橙累积最高峰至少推迟1个月左右。     

Phosphorus affects storage root yield of cassava through root numbers

Abstract

The objective of this study was to determine the effect of phosphorus applied through fertigation on growth and root yield of cassava. This was achieved through a greenhouse pot-experiment consisting of 1, 4, 7, 10, 20 and 30?mg?P?L^?1. Increasing P from 1 to 30?mg?P?L^?1 realized a 57.1 and 150.0% increase in leaf blade P in 2014 and 2015, respectively. Similarly, chlorophyll content and shoot growth increased as P concentration in solution increased. However, leaf stomatal conductance and net photosynthesis reached a maximum in 7 and 20?mg?P?L^?1 in 2014 and 2015, respectively. This trend of stomatal conductance and net photosynthesis was consistent with that of dry root yield and storage roots numbers. Regressing dry root yield against storage root numbers showed that R² = 0.80. Phosphorus encourages formation of storage roots and the duration of cassava’s growth affects the amount of P required for maximum root yield.     

西南桦以芽繁芽组培快繁研究

以8个月生苗木上采集的枝条作为外植体,通过激素、大量元素配比等试验,成功地研发出一套西南桦以芽繁芽组培快繁技术体系。其主要内容包括:1 选择邻近顶芽带腋芽的茎段作为外植体,用HgCl2消毒3min效果最佳,诱导成功率达10%;2 其侧芽诱导与增殖培养宜选用低浓度(0 2mg L-1)的IBA或NAA;3 大量元素配比满足K∶Ca=1∶0 04～0 08、K∶Mg=1∶0 02～0 04、N∶P=1∶0 02～0 03三个比例关系时,外植体侧芽能正常萌发生长,并迅速进入增殖状态,40d转接1次,增殖倍数在4倍以上;4 选用NAA浓度为0 50mg L-1的0 4MS培养基进行生根诱导,生根率达97 9%。     

Effects of water and exogenous Si on element concentrations and ecological stoichiometry of plantain (Plantago lanceolata L.)

Silicon (Si) is widely distributed in nature and can promote plant growth under various biotic and abiotic stresses. Drought stress seriously affects plant growth and the concentration and ecological stoichiometry of nutrients. Integrated nutrient management effectively protects plants from stresses. However, the role of water and Si availability on element concentrations and stoichiometry in plantain (Plantago lanceolata L.) are unclear. Accordingly, this study observed changes in the concentration and stoichiometry of macro- and micro-elements in plantain leaves supplied with various levels of Si under variable water availabilities through a greenhouse experiment. Supplemental Si increased Si concentration of leaves under both well-watered and drought conditions. Without supplemental Si, drought conditions decreased concentrations of carbon (C), C: nitrogen (N), C: phosphorus (P), silicon (Si):N, Si:P and increased concentrations of N, P, N:P, Si:C, calcium (Ca²⁺), magnesium (Mg²⁺), iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu). Increased Si under water stress increased concentrations of C, C:N, C:P, Si:C, Si:N, and Si:P, and decreased concentrations of Ca²⁺, sodium (Na⁺), and Mg²⁺. These results suggested that exogenous Si changed the concentrations and ecological stoichiometry of macro- and micro-elements.     

橡胶树大量元素研究概况

简述了橡胶树大量元素的作用与营养规律,针对目前橡胶园普遍存在肥力下降,氮、钾不足,磷肥利用率较低等情况,指出在天然橡胶树施肥过程中应优化肥料管理,进行平衡施肥、配方施肥,提高肥料利用率,对降低橡胶栽培生产成本,提高橡胶产量,保护环境和促进农业的可持续发展有重要意义.