What effect does iron have on peanut growth? What are the symptoms of iron deficiency?

Iron is an essential element for the synthesis of chlorophyll. Iron participates in redox reaction and electron transfer in peanut cells. Iron and organic matter can synthesize cytochrome, iron redox protein and bean hemoglobin, which play an important role in nitrate reduction and nitrogen fixation of rhizobia in peanut plants. Iron is also a component of some enzymes related to respiration.

When peanut is deficient in iron, the upper tender leaves turn green, while the lower old leaves and veins remain green. When iron deficiency is serious, the veins turn green first and then yellow, and all the new leaves on the upper part turn white, and the leaves gradually appear brown spots and necrosis, and then dry up and fall off. To identify whether plants are chlorosis due to iron deficiency, we can smear 0. 1% ferrous sulfate solution on the back of leaves, and if they turn green after 5 ~ 8 days, it can be confirmed as chlorosis due to iron deficiency.