As noted in Figure 1 below, the rate of photosynthesis in a plant depends on the plant temperature and, in turn, the amount of water available to the plant to regulate its temperature. When temperatures rise, plants need more water to cool themselves. If soil moisture is high, the demands for water can be met. But when temperatures rise and soil moisture is limited, the crop will experience heat stress.
During periods of stress, stomates may close to avoid cavitation, causing a reduction in photosynthesis, which can limit biomass production and reduce quality potential. Solar protectants, such as calcium-based Purshade®, have been shown to reduce leaf temperature, improve stomatal conductance, increase carbon assimilation, and enhance yield in various crops as a result of their ability to shield the plant from harmful ultraviolet (UV) and infrared (IR) radiation.
Figure 1
Roughly 90% to 95% of the water that moves into a plant is lost via transpiration, which in a crop such as tomatoes adds up to more than 640,000 gallons of water per acre per year. Even small gains in water use efficiency can add up to significant savings of water.
By reflecting heat-producing IR radiation, solar protectants help to keep the plant cooler, allowing for more efficient use of available water and photosynthesis to continue under solar-stress conditions.
By keeping the plant cooler, Purshade can help to:
- Extend the duration of photosynthetic activity during the day, enabling the plant to store the energy needed for biomass production during the later hours.
- Maintain normal transpiration.
- Improve respiration.
- Lower the crop water stress index.
- Use available water in the root zone, rather than lose it to gravitational pull or evaporation.
