CORRODED EXINES FROM HAVINGAS LEAF MOLD EXPERIMENT - STRUCTURE OF FAGUS AND QUERCUS EXINES

Structure of exine units of Fagus sylvatica L. and Quercus robur L. be came evident after six years in leaf mold. These exines appeared simil ar to those early in development and to exines on mature pollen follow ing laboratory experiments involving Gunnar Erdtman's acetolysis plus plasma ashing or oxidation with potassium permanganate. In Fagus the r od-shaped exine units showed a difference in diameter from a minimum o f 0.1 mu m at distal ends to 0.3 mu m or more basally. A core and an o uter binder zone were evident in these units. Material in the core zon e differed from the binder zone in having a weaker secondary electron signal. In Quercus, rods of exine unit structure were exposed. They we re, like ''experimentally'' oxidized pollen, about 0.1 mu m in diamete r. In severely corroded pollen of Fagus the ectexine appeared to be en tirely eroded except for the resistant exine units. Exine units appear ed to originate from the endexine.