Experiments on effects of phosphorus on the manganese nutrition of plants

Abstract

T h e effects a n d i n t e r a c t i o n s of t w o c o n c e n t r a t i o n s of p h o s p h o r u s a n d calcium, a n d four c o n c e n t r a t i o n s of m a n g a n e s e , were i n v e s t i g a t e d in c o t t o n grown in q u a r t z chips w i t h n u t r i e n t solutions. Too little p h o s p h o r u s a n d calcium a n d t o o m u c h m a n g a n e s e caused a b n o r m a l plants, b u t w i t h suitable c o n c e n t r a t i o n s of t h e t h r e e n u t r i e n t s p l a n t s were healthy. W i t h t h e largest c o n c e n t r a t i o n s of t h e t h r e e n u t r i e n t s t o g e t h e r m u c h of t h e m a n g a n e s e t a k e n up p r e c i p i t a t e d as nodules in t h e leaves; a large c o n c e n t r a t i o n of calcium seemed necessary for p r e c i p i t a t i o n a n d to p r e v e n t h a r m f u l c o n c e n t r a t i o n s of mobile m a n g a n e s e in t h e plants. T h e results i n d i c a t e d t h a t in p l a n t s grown w i t h m u c h m a n g a n e s e its c o n c e n t r a t i o n in leaves increased as more calcium a n d p h o s p h o r u s were given w h e n t h e i r mole ratio in t h e n u t r i e n t solution was less t h a n 1 ; b u t t h e c o n c e n t r a t i o n of leaf m a n g a n e s e d i m i n i s h e d w h e n t h e ratio was g r e a t e r t h a n 1.