Question

Why does wilting occur in herbaceou plants?​

Answer 1

Answer:

When the soil of a plant runs too low of available water, the water chains in the xylem become thinner and thinner due to less water.  

Effectively, the plant is losing water faster than it is absorbing it. When this happens, the plant loses its turgidity and begins to wilt.

Low soil moisture is often the reason this happens but other factors play a role. When temperatures are high and it is warm or hot, the plant loses more water through transpiration causing the plant to wilt if the water needs are higher than what is available.  

Likewise, if the air is especially dry, wilting can occur quickly. Plants with higher water needs will wilt much faster than plants with low water needs like cacti and other succulents. For example, Spathiphyllum (Peace Lily) are notorious for wilting very easily but will perk back up quickly when watered.  

Occasionally, vascular fungal diseases will clog the xylem tissue and cause wilting. Verticillium wilt is a common example and is often seen in tomatoes and trees.

Explanation:

Answer 2

Answer:

Too much water, caused by excessive watering or heavy rain, can lead to a plant wilting. ... Excess water near a plant's root collar can also cause diseases, such as root rot. Root rot and other fungal diseases fostered by a wet environment can also cause wilting.

When the soil of a plant runs too low of available water, the water chains in the xylem become thinner and thinner due to less water. ... When this happens, the plant loses its turgidity and begins to wilt.