HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Chaney, W. R. Articles by Strickland, R. C. Search for Related Content PubMed Articles by Chaney, W. R. Articles by Strickland, R. C. Agricola Articles by Chaney, W. R. Articles by Strickland, R. C.

Relative Toxicity of Heavy Metals to Red Pine Pollen Germination and Germ Tube Elongation¹

ABSTRACT

Heavy metals are known to affect vegetative growth of plants, but little is known concerning the effects of these environmental pollutants on reproductive processes. Hence, the effects of Cd²⁺, Hg²⁺, Pb²⁺, Cu²⁺, Zn²⁺, and Ba²⁺ on red pine (Pinus resinosa Ait.) pollen germination and germ tube elongation were determined in vitro in a series of nine aqueous solutions with concentrations that ranged from 0.56 µmol L^–1 to 71.16 µmol L^–1 for each cation. Large differences among metals in inhibition of the two growth parameters were found. Based on the lowest concentration significantly inhibiting germination, Cd²⁺ was the most toxic ion followed by Cu²⁺ > Hg²⁺ > Pb²⁺ >> Zn²⁺ > Ba²⁺. Similarly, the order for metal inhibition of tube elongation was Cd²⁺ > Pb²⁺ > Hg²⁺ = Cu²⁺ >> Zn²⁺ > Ba²⁺. Compared with the other ions, Zn²⁺ and Ba²⁺ were relatively nontoxic. The concentration (effective dose) of each metal necessary to produce a 10% reduction of germination and tube elongation (ED₁₀) was calculated from linear regression equations. The ED₁₀ for germination for Cd²⁺ was 0.27 µmol L^–1 and was 2.2, 2.5, and 19.0 times less than the ED₁₀ for Hg²⁺, Cu²⁺, and Pb²⁺, respectively. In comparison, the Cd²⁺ ED₁₀ for germ tube growth was 1.00 µmol L^–1. Although the concentrations of Cd²⁺, Hg²⁺, and Pb²⁺ that produced inhibitory effects in vitro occur in the environment, extrapolation of these results to in vivo conditions is cautioned.

Key Words: cadmium • lead • zinc • copper • mercury • barium

¹ Contribution from Purdue Univ. Agric. Exp. Stn., Journal Paper no. 9594.

² Professor of Physiological Ecology, Dep. of Forestry and Natural Resources, Purdue Univ., W. Lafayette, IN 47907 and Office of Chemical Development, TVA, Muscle Shoals, AL 35660.

Received for publication August 25, 1983.