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 Gausman, H. W. Articles by Leamer, R. W. Search for Related Content PubMed Articles by Gausman, H. W. Articles by Leamer, R. W. Agricola Articles by Gausman, H. W. Articles by Leamer, R. W.

Reflectance Differences Between Target and Torch Rape Cultivars¹

To characterize and explain leaf and plant reflectance differences between Target (Brassica napus L.) and Torch (Brassica campestris L.) rape cultivars, laboratory spectrophotometric reflectance measurements were made on leaves of the same age, collected from different nodes, and on leaves of different ages, collected from the same node, for both small (five leaves) and large (nine leaves) Target and Torch plants. Spectroradiometric reflectance measurements were made on Target and Torch plants (four and five leaves, respectively) that were growing in 0.09 m² soil-containing flats. Torch's spectrophotometric single leaf reflectance was consistently lower than Target's at the 650-nm chlorophyll absorption band because Torch's chlorophyll concentration was larger than Target's, which caused more red light absorptance. Spectroradiometric measurements indicated that: (1) wet soil strongly absorbed visible light (500 to 700 nm) so that Target's soil-containing flat with 60% plant cover had less reflectance than Torch's soil-containing flat with 75% plant cover, (2) Torch (most foliage) had higher near-infrared (750 to 1,350 nm) reflectance than Target (least foliage), and (3) the 2,200-nm wavelength is a candidate band to distinguish Target from Torch. The difference in chlorophyll concentrations between Target and Torch, compared with leaf structural differences, is apparently the most important factor that would affect the infrared color film's tonal response to vegetation in the photographic sensitive region (500 to 900 nm).

Key Words: Spectrophotometer • Chlorophyll • Soil • Leaf structure • Infrared color film • Remote sensing

² Supervisory plant physiologist and soil scientist, respectively, USDA, Weslaco, TX 78596.

Received for publication September 22, 1980.