Some Effects of Iron Deficiency on Flowering of Xanthium

Abstract

1. Cocklebur plants (Xanthium pensylvanicum Wallr.) exhibiting iron-deficiency symptoms during photoinductive treatment either did not flower subsequently or flowered abnormally when maintained on complete nutrient solution. 2. The abnormal flowering was characterized by (a) the delayed appearance and slower development of terminal staminate inflorescence primordia, (b) the development of pistillate inflorescences, which were surrounded by rosettes of many leaves, and (c) the failure of pistillate inflorescences to produce mature burs. 3. Plants which had recovered from iron deficiency and were then subjected to photoinductive treatment flowered normally. 4. A low carbohydrate level in - Fe plants during induction is apparently not responsible for their abnormal flowering, since - Fe plants supplied with 10% sucrose solution during photoinductive treatment also flowered abnormally. The - Fe plants supplied with sucrose soon exhibited more vigorous stem elongation than did - Fe plants not given sucrose, ...