What are the damages of high temperature weather on corn?

Classification of high temperature heat damage levels in corn: Corn heat damage indicators, based on moderate heat damage, are 36°C in the seedling stage, 32°C in the reproductive stage, and 28°C in the mature stage. Temperatures higher than 32°C in the flowering stage are not conducive to pollination. Based on the average temperature during the entire growth period, mild heat damage is 29°C, with a yield reduction of 11.9%; moderate heat damage is 33°C, with a yield reduction of 52.9%; severe heat damage of 36°C will result in total production. High temperatures of 38-39°C cause high temperature heat damage. The longer it lasts, the more severe the damage will be and the more difficult it will be to recover. The main effects of high temperature on corn growth are as follows:

1. Effect on photosynthesis. Under high temperature conditions, the activity of photosynthetic proteases decreases, the chloroplast structure is destroyed, causing stomata to close, thereby weakening photosynthesis; on the other hand, under high temperature conditions, respiration increases, consumption increases, and dry matter accumulation decreases. The longer the high temperature stress at 38-39°C lasts, the more serious the damage will be to the plants, the more difficult it will be to recover, and the longer it will take.

2. Shorten the reproductive period. High temperature forces various physiological and biochemical reactions to accelerate during the growth process of corn, and shortens each growth stage. If the ear differentiation time is shortened, the number of differentiated florets in the ear will be reduced, and the ear will become smaller. High temperatures in the late growth period cause corn plants to die prematurely, or end the growth process prematurely and enter the maturity stage. Grain filling time is shortened, dry matter accumulation is reduced, and thousand-kernel weight, test weight, yield and quality are reduced.