Maximum Yield USA 2015 January | Page 68

finding the fountain of youth Maintaining a Healthy Root Zone We have seen how important it is to control the aboveground conditions while supplying plant growth regulators, but enhancing the rhizosphere, or root zone, has huge benefits as well in delaying senescence. Growers who ensure adequate availability of moisture and solubility of nutrients in soil solutions can delay senescence, as excessive moisture levels in the root zone reduces oxygen concentrations and can hinder the exchange of nutrients. Saturated soil promotes roots that shelter themselves from the elements as they form a waxy-like surface upon them called suberin. The cork-like layer shields the damaging effects of increased moisture stress, lowering yields dramatically. “Growers who ensure adequate availability of moisture and solubility of nutrients in soil solutions can delay senescence. " Reducing Environmental Stressors The deaths of individual cells in tissues such as the xylem appear to be controlled by internal factors, but senescence often depends on a steady state. To keep producing, plants need a constant microclimate harmonious to life. The redistribution of nutrients to actively growing parts of the plant is greatly affected by the climate of the day. Plants in drought stress react by reducing the function of xylem channels, hindering the transport of water and nutrients, limiting plant productivity and greatly reducing yields. Buds and fruits exposed to these conditions rush headlong towards death in their hurry to complete the life cycle and ensure the viability of the next generation. Not only is it critical to control these cumulative conditions, the effect of even moderate drought stressors can damage xylems and often leads to fruit poor set, cracking, pitting, splitting and blossom end rot as well as poor overall fruit quality and taste. 66 Maximum Yield USA  |  January 2015