The main nutrient involved in plant nutrition is thecarbon , extracted from the carbon dioxide from the air by plants autotrophic through the process of photosynthesis . Plants do not chlorophyll , called heterotrophs depend on autotrophs for nourishment charcoal.
Nutritional uses absorption processes gas and solutions minerals and directly into the water to the lower plants and aquatic plants , as in the case of vascular plants in the nutrient solution from the soilby the roots or in the air by leaves .
The roots, trunk and leaves are the organs of vascular plant nutrition: are the vegetative apparatus . Hairs by their roots (rootlets), the plant absorbs the soil solution, ie water and mineral salts , which are the raw sap (it happens that the roots are associated with fungi to better absorb the soil solution , one speaks of mycorrhiza ).
For the leaves, where it makes the photosynthesis , the plant receives amino acids and sugars that are the elaborated sap . Under the leaves, the stomata allow the evaporation of a portion of waterconsumption (oxygen: O2) and the absorption of carbon dioxide (CO2).
For the stem , the two types of circulating sap the raw sap the phloem sap and elaborated by the xylem .
The macronutrients
The macronutrients are characterized by concentrations above 0.1% of dry matter. Among them are the major nutrients needed for plant nutrition, which are the carbon , the hydrogen , the oxygen andnitrogen . These four components of the organic matter represent more than 90% of the average dry matter of the plant. To which are added the elements used as fertilizer and amendments that are thepotassium , the calcium , the magnesium , the phosphorus and the sulfur .
