Essential Plant Nutrients PLSC-250 Chapter 4

17 Essential Plant Nutrients Carbon, Hydrogen & Oxygen Primary Nutrients ( N, P,K) Secondary Nutrients (S, Mg, Ca) Micro Nutrients(B, Mn, Cu, Zn,Fe, Mo, Cl, Ni)

CHO Carbon- Forms back bone of plants. Photosynthesis is key. Hydrogen- Water transport Oxygen-important is respiration.

Primary Nutrients Nitrogen Function-growth and green color Deficiency- stunted growth, pale yellow older leaves Absorbed N03-, NH4+

Primary Nutrients Phosphorous Stimulates early growth and root formation, promotes seed production Deficiency-slow growth, purplish color Absorbed H2PO4-, HPO42-

Primary Nutrients Potassium Function-improves resistance to disease & cold. Aids in CHO production Deficiency-slow growth,scorched effect Absorbed-K+

Secondary Nutrients Calcium Function Aids in movement of CHO in terminal buds Deficiency- Terminal bud dies, blooms shed early Absorbed-Ca2+

Secondary Nutrients Magnesium Function-ingredient of chlorophyll aids in translocation formation of oils and fats Deficiency-yellowing of lower leaves curl up Absorbed-Mg 2 +

Secondary Nutrients Sulfur Function-aids in the formation of oils and certain proteins. Deficiency-lower leaves yellow-green, stems and roots small. Absorbed SO42-

Micronutrients Zinc ( zinc ion Zn++) It controls the synthesis of indoleacetic acid, an important growth regulator. Deficiency – Terminal growth areas are affected first. Citrus & other tree crops. Symptoms – decrease in stem length & rosetting of terminal leaves, Reduced fruit buds, Mottled young leaves, Dieback of twigs after first year, Striping or banding on corn leaves.

Micronutrients Iron ( Fe++) An activator for respiration, photosynthesis, and symbiotic nitrogen fixation. Symptoms – Interveinal chlorosis of young leaves. Veins remain green except in severe cases., Twig dieback, In severe cases, death of entire limbs or plants.

Micronutrients Manganese (ion Mn++) An activator for enzymes in plant growth. Symptoms – Interveinal chlorosis of young leaves. Gradation of pale-green leaf coloration, with darker color next to veins., There is no sharp color distinction between veins & interveinal brown spots or streaks (barley) or necrotic spots (potatoes)

Micronutrients Copper (ions Cu+ & Cu++) An activator of several plant enzymes & may play a role in Vitamin A production. Symptoms – Stunted growth., Dieback of terminal shoots in trees., Poor pigmentation., Wilting & eventual death of leaf tips., Formation of gum pockets around central pith in citrus.

Micronutrients Boron (boric acid H3BO3) Functions in plants in the differentiation of meristematic tissue. Symptoms – Reduced flower or improper pollination., Death of terminal growth, causing lateral buds to develop, producing a “witch’s broom” effect., Thickened,, curled, wilted, & chlorotic leaves., Soft or necrotic spot in fruit or tubers

Micronutrients Molybdenum (molybdate ion MoO4=) Need by plants to utilize nitrogen Symptoms –Stunting & lack of vigor. This is similar to nitrogen deficiency, because of the key role molybdenum in nitrogen utilization., Marginal scorching & cupping or rolling of leaves., “Whiptail” of cauliflower., Yellow spotting of citrus.

Micronutrients Chlorine (ion Cl-) Required for photosynthetic reaction in plants & regulating cell turgor potential. Symptoms – Spotting of leaves of small grains, first on older leaves & more severe toward the tip half of the leaf blade., Delayed maturity.

Micronutrients Nickel (divalent cation Ni++) Used in the conversion of urea to ammonia in plant tissue – overall nitrogen metabolism. Symptoms – Chlorosis of young leaves., Death of meristem.