Question

.In her garden Rekha observed that the colour of some leaves is darker than others. It is due to deficiency of

a. Calcium b. Phosphorous c. Nitrogen d. Potassium

please answer me quickly​

Answer 1

Colours of some leaves is darker than others. It is due to the deficiency of Phosphorous.

Explanation:  

Role of Phosphorous in plants

• Phosphorus is an essential nutrient for plant growth and development.  After nitrogen, it is the second most limiting macronutrient
• It catalyzes various biochemical reactions as well as the development of plant structures. It converts solar energy into components that are useful to plants.    

Phosphorous deficiency in plants

• The first sign of phosphorus deficiency is stunted growth .Some crops, such as corn, tend to show abnormal discoloration in various parts of the plant (mainly leaves).  

• During early vegetative stages, the leaves and stems of plants turn dark green and appear stunted. This is due to the deficiency of phosphorous. Sometimes the leaves changes into  purple color due to the accumulation of sugars in the leaves, which promote anthocyanin ( a purple pigment) synthesis.  

• Unlike many other elements, phosphorus is highly mobile in plants. Therefore, phosphorus deficiency can translocate from older tissues to young, actively growing tissues. These symptoms first show up in the older plant tissues.
• Due to the redistribution of phosphorus, older plant leaves are affected before the younger  leaves. Lower leaves and stems of corns may display a purple or reddish color.
• Phosphorus deficiency is caused by a variety of factors including pH, clay type, organic content, soil temperature, aeration, moisture, etc.,