calcium nutrition
“ CALCIUM TRANSPORT DISORDERS
such as tip burn and blossom end rot also have a strong genetic element , and many modern cultivars of lettuce and tomato have had some degree of tip burn and blossom end rot resistance bred into them .”
Externally visible blossom end rot can occur on relatively young tomato fruit .
Calcium Uptake
Calcium is somewhat different from the other macroelements as its uptake and transportation within the plant is driven largely by transpiration . Transpiration is the loss of water from the leaf surfaces through stomata , which are open for photosynthesis . As moisture is lost from the foliage , suction is created , which draws more water up through the internal transpiration stream . This flows within the xylem vessels of the plant from root system up to the leaf tips , developing buds , flowers , and fruits . It is this transpiration stream , driven by water loss from the foliage , that carries all the calcium through the plant . Under certain environmental conditions that restrict transpiration , water and calcium are not driven to the young developing tissue fast enough and cellular break down starts to occur . These are typically warm , humid conditions combined with limited airflow and rapid growth rates , often referred to as “ calcium stress periods .” Any part of the plant that is at the very end of the transpiration stream , therefore , is the first to suffer from cellular breakdown due to insufficient calcium . This includes leaf tips , growing points , and the distal end of tomato fruit , resulting in blossom end rot . If the crop is currently growing at a rapid rate , this lack of calcium deposition in new cells becomes far more diluted and symptoms more severe . Calcium transport disorders such as tip burn and blossom end rot also have a strong genetic element , and many modern cultivars of lettuce and tomato have had some degree of tip burn and blossom end rot resistance bred into them .
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