Fig. 1. Wilted and stunted cabbage plants growing in a semicircle adjacent to a black walnut tree. Note large, healthy plants in foreground, side and background about a semicircle of smaller, wilted plants, growing in an area affected by the root system of the black walnut tree.
These two instances of wilting and stunting of plants in the vicinity of walnut trees give further circumstantial evidence that the trouble might have been caused by the toxicity or antagonism of black walnut roots. Detailed experiments with the plants in question would have to be run to prove this assumption.
Preliminary Studies on Catkin Forcing and Pollen Storage of Corylus and Juglans
L. G. Cox, Cornell University
Methods of collecting and storing pollen are of great interest to those engaged in plant breeding. Very little reliable information is available for the various nut species compared with many other horticultural plants. The following preliminary experiments were conducted to obtain data on germination media, forcing methods, and storage conditions for Corylus and Juglans Sieboldiana pollen. The former was mostly from hybrid plants produced by crossing the Rush filbert (Corylus americana) with European varieties.
The optimum temperature and sugar concentration for germination of Corylus pollen.
The cut ends of Corylus branches with mature catkins collected March 1, 1942 were immersed in water and forced into shedding pollen in a room at a temperature of approximately 20° centigrade. The collected pollen was sifted upon the surface of a thin layer of sugar-agar in petri dishes.
Commercial cane sugar was used in preference to purified sucrose, because other studies have shown it to contain impurities which stimulate pollen germination. A range in sugar concentration from 5% to 55% by weight in 5% intervals was made up in distilled water containing 1.5% agar, heated to boiling and poured into the petri dishes.