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 MacKown, C. T. Articles by Rothwell, C. G. Search for Related Content PubMed Articles by MacKown, C. T. Articles by Rothwell, C. G. Agricola Articles by MacKown, C. T. Articles by Rothwell, C. G.

Nitrate Uptake and Assimilation and Chlorate Tolerance of Wheat

USDA-ARS, National Agric. Water Quality Lab., P.O. Box 1430, Durant OK, 74702
Dep. of Agronomy, Univ. of Kentucky, Lexington, KY 40546-0091
USDA-ARS, Tobacco and Forage Res. Unit, and Dep. of Agronomy, Univ. of Kentucky, Lexington, KY 40546-0091

^* Corresponding author.

Productivity of nonlegume crops depends partly on nitrate uptake and reduction. To study the nitrate assimilation pathway of plants, the herbicide chlorate has been exploited as an analog of nitrate. Marked variations in visible leaf chlorosis among 15 soft red winter wheat (Triticum aestivum L.) seedlings exposed to 120 µM chlorate were reported by others. From their study, we selected three chlorate-tolerant and three chlorate-sensitive ranked cultivars and measured influx and assimilation of ¹⁵N-nitrate to determine if these traits were related to differences in chlorate sensitivity. Effects of 120 µM chlorate on growth, leaf chlorophyll concentration, and nutrition were also quantified. The growth and chlorophyll levels of main stem oldest leaf blades decreased in the presence of chlorate in all cultivars except for one chlorate-tolerant cultivar. Neither the level of tissue nitrate nor the influx and assimilation of ¹⁵N-nitrate was related to chlorate sensitivities we observed, or those previously reported for the six selected cultivars. Chlorate toxic effects unrelated to nitrate assimilation and interactions between absorbed nitrate and chlorate and their compartmentation may alter the response of these cultivars to chlorate. Inferences that chlorate sensitivity of wheat is related to nitrate uptake and assimilation appeared to be inappropriate.

Received for publication May 8, 1995.