Effects of long-chain aliphatic compounds on the germination and initial growth of corn, radish and spinach seedlings, and on hydrological properties of a sand growth medium

Abstract

A greenhouse and laboratory study was carried out to determine the effects of various amounts (0.5–2.0%) of long-chain aliphatic compounds (LCA) of beeswax on the germination and initial growth (25 d) of corn, radish and spinach seedlings, and on the hydraulic properties of the sand growth medium. Complete emergence was obtained for corn, irrespective of aliphatic addition, whereas, the germination rate of the other two species decreased gradually as the amount of aliphatics added increased. With 2% LCA, 40 and 60%, respectively, of radish and spinach seeds failed to germinate. Dry matter yields of the three crops were reduced by the incorporation of aliphatics. The inhibitory effect of LCA on radish and spinach seedlings, coupled with a reduced plant density, resulted in a more dramatic yield reduction. Although there was a slight increase in the total porosity of the sand treated with LCA, the addition of LCA markedly decreased amounts of pores in the 25- to 100-μm class. It was concluded that the LCA influenced seed germination to various degrees, depending on the plant species, and that these compounds had a definite inhibitory effect on growth of seedlings, mainly through changes in the hydraulic properties of the sand. Key words: Long-chain aliphatics, germination, hydraulic properties