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Fluid Journal : Spring 2015
7 The Fluid Journal Spring 2015 Calcium Offers Most Crop Per Drop Of key importance in promoting water-use efficiency The Fluid Journal • Official Journal of the Fluid Fertilizer Foundation • Spring 2015 • Vol. 23, No. 2, Issue #88 In previous Fluid Journal editions, we were informed about current water scarcity problems and the challenges created for production agriculture. This topic is very timely since it is elementary that plants and fertilizer will neither survive nor function without water. In these articles, the authors suggested increasing the efficiency of our water use via: 1. Optimum irrigation systems 2. Limiting water loss during delivery to the systems. But, can we optimize plant water usage as well? Can specific nutrients applied during fertilization maximize available water uptake/usage by plants? Recent research during the past few decades indicates that nutrients can play a vital role in plant (WUE). Specifically, calcium fertilization will be the focus of our attention here. Calcium’s role We learned long ago that calcium is essential for cell wall development/ thickness, plasma membrane structure/ water regulation as well as nutrient uptake, and cell division or mitosis. We now know that calcium and calmodulin (calcium modulated protein—CaM) act as a messenger molecule to initiate plant protection mechanisms, aid in hormone responses and control plant water relationships. How then, does calcium/ CaM help increase a plant’s (WUE)? Growth under drought In the chloroplasts of plant cells, oxygenated radical compounds are formed during photosynthesis. Under normal growing conditions, these compounds are eliminated by the plant. But during drought stress, they can accumulate and attack and damage the plasma membranes of cells, causing water and nutrient leakage at the cellular level. To control these radical compounds, the plant releases mobile Ca stored in vacuoles to stabilize and maintain plasma membrane integrity, as well as control oxygenated radical concentrations. Therefore, we can observe the effect of calcium mitigating oxygen radical (H2O2- hydrogen peroxide) concentrations in plants under drought stress (Figure 1). Maximizing cellular water content with minimal damage to the plasma membrane is the result (Figure 2). Without water soluble calcium availability to the plant, damage to the plasma membrane can: • greatly reduce the water content of plants during drought stress • reduce plant growth • limit yield. Water uptake To maximize water uptake efficiency, Dr. Bill Easterwood Summary: Amongst the tools we have available for effective crop production is calcium fertilization. Its beneficial effects in terms of crop yield, fruit quality, and plant health are well known. Most importantly, it increases water use efficiency (WUE) and can be incorporated into a drought stress management plan. ▼ DOWNLOAD