Explain why osmotic balance is key to survival of plants under drought
Osmotic balance refers to the maintenance of proper water balance within a plant's cells and tissues. It is key to the survival of plants under drought conditions because drought causes a reduction in the availability of water, resulting in water stress for the plant. During drought, plants experience water deficits in the soil, which reduces the amount of water taken up through the roots. This leads to a decrease in internal water content, especially in the cells and tissues of the plant.
To survive under drought, plants need to maintain their osmotic balance to prevent excessive water loss and maintain proper cellular functions. Here are a few reasons why osmotic balance is crucial for plant survival under drought:
1. Maintaining turgor pressure: Turgor pressure is the pressure exerted by the fluid content within plant cells against the cell wall. It helps to keep the cells firm and upright, supporting the overall structure of the plant. During drought, the loss of water from cells can cause a decrease in turgor pressure, leading to wilting and wilting-related damage. By maintaining osmotic balance, plants can regulate the movement of water into and out of cells, ensuring adequate turgor pressure is maintained even under drought conditions.
2. Preventing dehydration and desiccation: Dehydration occurs when plant cells lose water to the surroundings, while desiccation refers to the complete drying out of plant tissues. Without proper osmotic balance, water can easily escape from the plant cells, exacerbating the effects of drought. By regulating osmotic pressure, plants can control water movement and reduce the risk of dehydration and desiccation, which can be lethal if not properly managed.
3. Facilitating nutrient uptake: Water is essential for the uptake and transport of nutrients from the soil to various parts of the plant. Under drought conditions, water availability is limited, making nutrient absorption more challenging. Osmotic balance helps maintain the necessary water uptake by facilitating the movement of water and dissolved nutrients between plant cells. This ensures that the plant can still acquire the necessary nutrients for growth and survival, even in the face of water scarcity.
4. Protecting cellular integrity: Proper osmotic balance is crucial for maintaining the structural and functional integrity of plant cells. When water availability decreases, plant cells may experience excessive shrinkage, leading to cellular damage. By regulating osmotic pressure, plants can prevent extreme cell shrinkage or bursting, thus ensuring the cellular architecture and integrity are preserved.
Overall, osmotic balance is key to the survival of plants under drought as it helps to maintain turgor pressure, prevent dehydration, facilitate nutrient uptake, and protect cellular integrity. By maintaining proper osmotic balance, plants can adapt to water-limited environments and increase their chances of surviving and thriving during drought periods.