Phosphorus in plant physiology P content of plants Approximately 0.2% of plant dry weight is P Plants require a relatively large amount of P. The phosphate concentration in the cytosol is maintained at fairly constant concentrations in the 5 to 8 mol/m3 regardless of the external phosphate concentration except under severe P deficiency. By contrast is the vacuolar phosphate concentration

Plant nitrogen 1.1 Uptake of N 1. N is required by plants in large amounts Most plant material contains 2-4%N and 40%C. 2. N is usually the limiting nutrient in unfertilized systems 3. Most n is taken up from the soil in the form of nht or no a small amount of NH3 can be absorbed through the leaves N2 can be used by legume plant via biological nitrogen fiXation

The principles of application fertilizers Law of the Minimum: the crop's yield is restricted by the lack of one element, even Mg- al Zn S though there may be sufficient quantities of all the

Soil fertil Soil fertility is the characteristics of soil that enables it to Provide nutrients in adequate amounts in adequate time In appropriate balance for growth of particular plant(s)

Factors effecting the plant uptake 影响养分吸收的因素主要包括介质中的养分浓度、温 度、光照强度、士壤水分、通气状况、土壤pH值、养分离 子的理化性质、根的代谢活性、苗龄、生育时期植物体内养 分状况等

Foliar fertilizer A foliar fertilizer is one that is applied to the surface of the plant. a Foliar uptake is important to aquatic plants and when nutrients are sprayed on foliage in horticulture and agriculture

The short distance transports of nutrients There are two main steps nutrients translocation in plant after nutrients absorbed by the root. One is the centripetal transport from the rhizoplane through the cortex tissue of the roots towards the xylem vessels of the central cylinder. Another one is the vertical transport from from the root towards the leaves

磷是作物必需的三要素之一 磷肥是世界上仅次于氮肥的主要肥料产品 磷在自然界中一般不以游离态(元素态)存在,而以磷酸盐形 式存在于矿物中。最常见的含磷矿物是磷灰石,通式为 Ca5X(PO4)3,其中X代表一F,-OH或-Cl等。最常见的氟磷灰 石的化学式为CaF(PO4)3。1989、1990年度,我国生产各种磷肥 453万吨(P2O5),居世界第二位

一、概述 二、主要氮肥的品种及性质 三、氮肥的合理施用

第一节植物的营养成分 一、植物的组成和必需营养元素的概念