With its citations, describe all plant essential elements, their deficiency symptoms and their toxicity effects?

Plant essential elements are classified into two categories: macronutrients and micronutrients. Macronutrients are required in large quantities, while micronutrients are needed in smaller amounts.

1. Macronutrients:
a) Nitrogen (N):
- Deficiency symptoms: Stunted growth, yellowing of older leaves (chlorosis), reduced fruit and seed production.
- Toxicity effects: Excessive vegetative growth, delayed flowering, reduced fruit quality.

b) Phosphorus (P):
- Deficiency symptoms: Stunted growth, purplish discoloration of leaves, delayed maturity.
- Toxicity effects: Reduced nutrient uptake of other elements, leading to deficiencies in other nutrients.

c) Potassium (K):
- Deficiency symptoms: Yellowing and necrosis of leaf margins, reduced fruit quality.
- Toxicity effects: Reduced uptake of magnesium and calcium, leading to deficiencies in these elements.

d) Calcium (Ca):
- Deficiency symptoms: Stunted growth, distorted leaves, blossom end rot in fruits.
- Toxicity effects: Rare, but excessive calcium can interfere with the uptake of other cations.

e) Magnesium (Mg):
- Deficiency symptoms: Interveinal chlorosis, leaf curling, reduced growth.
- Toxicity effects: Rare, but excessive magnesium can interfere with the uptake of other cations.

f) Sulfur (S):
- Deficiency symptoms: Chlorosis of younger leaves, stunted growth.
- Toxicity effects: Rare, but excessive sulfur can reduce plant growth and cause nutrient imbalances.

g) Carbon (C), Hydrogen (H), and Oxygen (O):
- These elements are obtained from air and water and are not typically associated with deficiency or toxicity symptoms.

2. Micronutrients:
a) Iron (Fe):
- Deficiency symptoms: Interveinal chlorosis of young leaves.
- Toxicity effects: Rare, but excessive iron can cause leaf bronzing and reduced growth.

b) Manganese (Mn):
- Deficiency symptoms: Interveinal chlorosis, reduced growth.
- Toxicity effects: Reduced uptake of iron and other cations, leading to deficiencies.

c) Zinc (Zn):
- Deficiency symptoms: Stunted growth, interveinal chlorosis, reduced fruit production.
- Toxicity effects: Reduced uptake of iron and manganese, leading to deficiencies.

d) Copper (Cu):
- Deficiency symptoms: Stunted growth, wilting, chlorosis.
- Toxicity effects: Rare, but excessive copper can cause leaf necrosis and reduced growth.

e) Molybdenum (Mo):
- Deficiency symptoms: Stunted growth, yellowing of older leaves.
- Toxicity effects: Rare, but excessive molybdenum can cause leaf scorching and reduced growth.

f) Boron (B):
- Deficiency symptoms: Stunted growth, distorted leaves, reduced fruit production.
- Toxicity effects: Reduced root growth, leaf necrosis, reduced growth.

g) Chlorine (Cl):
- Deficiency symptoms: Rare, but can cause wilting and reduced growth.
- Toxicity effects: Rare, but excessive chlorine can cause leaf necrosis and reduced growth.

h) Nickel (Ni):
- Deficiency symptoms: Rare, but can cause reduced growth and delayed maturity.
- Toxicity effects: Rare, but excessive nickel can cause leaf necrosis and reduced growth.

It's important to note that the symptoms and effects mentioned above may vary depending on the plant species and environmental conditions.