My Account: Log In | Join | Renew
Search
Author
Title
Vol.
Issue
Year
1st Page

Abstract

 

This article in CS

  1. Vol. 19 No. 5, p. 635-640
     
    Received: Sept 5, 1978
    Published: Sept, 1979


 View
 Download
 Alerts
 Permissions
 Share

doi:10.2135/cropsci1979.0011183X001900050022x

Senescence in Field-grown Wheat1

  1. Thomas G. Patterson and
  2. Dale N. Moss2

Abstract

Abstract

We examined the senescence pattern of hard red spring wheat (Triticum aestivum L. em Thell) grown in a field environment. The upper five leaf blades and sheaths of the canopy were analyzed for chlorophyll, chlorophyll a/b ratio, protein, and free amino acids. An estimation of the photosynthetic activity of these organs was made by measuring the uptake of 14CO2. The photosynthetic activity of the canopy reached a maximum after anthesis, then declined rapidly thereafter. Lamina chlorophyll content reached a maximum at the time of full expansion and declined continuously thereafter. Sheath chloropyll followed a different pattern of accumulation and degradation than that of the lamina and declined more slowly than the lamina chlorophyll content. Chlorophyll a/b ratio of the leaf blades was found to vary with the position in the canopy, with lower blades having a declining a/b ratio and the upper leaves a constant ratio. The sheaths had a constant a/b ratio. Protein content of the leaf blades was highest at full expansion and decreased with age. Sheath protein was essentially constant over the season. Free amino acids content of both the lamina and sheaths showed a dramatic increase prior to anthesis, then declined thereafter. None of the components measured correlated well with the photosynthetic activity of the canopy. For this reason they were judged to be unacceptable as screening techniques for leaf senescence.

  Please view the pdf by using the Full Text (PDF) link under 'View' to the left.

Copyright © .