About Us | Help Videos | Contact Us | Subscriptions

Members of ASA, CSSA, and SSSA: Due to system upgrades, your subscriptions in the digital library will be unavailable from May 15th to May 22nd. We apologize for any inconvenience this may cause, and thank you for your patience. If you have any questions, please call our membership department at 608-273-8080.


Institutional Subscribers: Institutional subscription access will not be interrupted for existing subscribers who have access via IP authentication, though new subscriptions or changes will not be available during the upgrade period. For questions, please email us at: queries@dl.sciencesocieties.org or call Danielle Lynch: 608-268-4976.



This article in CS

  1. Vol. 35 No. 4, p. 1063-1069
    Received: Sept 20, 1994

    * Corresponding author(s): agr036@ukcc.uky.edu
Request Permissions


Carbon and Nitrogen Supply during Seed Filling and Leaf Senescence in Soybean

  1. R. Hayati,
  2. D. B. Egli  and
  3. S. J. Crafts-Brandner
  1. J urusan Budidaya Tanaman, Fakultas Pertanian, Universitas Sriwijaya, J.L. Padang Salasa, Palembang, Indonesia
    D ep. of Agronomy, Univ. of Kentucky, Lexington, KY 40546-0091
    U SDA-ARS, Western Cotton Res. Lab., Phoenix, AZ 85040



Leaf senescence and N redistribution during seed filling may limit soybean [Glycine max (L.) Merr.] yield by restricting the seed filling period. Experiments were conducted in the field and greenhouse to evaluate the relationship between seed N demand and leaf senescence. Plants (cv. McCall) were grown under shade cloth (which reduced insolation by 63%) from R1 to R5 (beginning seed fill), then the shade was removed from some plants with the objective of increasing photosynthesis, seed dry matter, and N accumulation. Experiments included plants grown in soil with no nodules (NO3 as primary source), plants grown in soil with many nodules (N from NO3 and N2 fixation), and in a hydroponics system (NO3 as primary N source) where N was removed from the media at R5. Increasing photosynthesis at R5 increased seed dry matter accumulation and the response was larger when N was available. Seed N accumulation also increased if N was available. Increasing photosynthesis had no effect on seed N accumulation when N was not available to the plant. Temporal changes in chlorophyll and N of an upper leaf were measured to characterize leaf senescence. Increasing photosynthesis did not accelerate leaf senescence in any of the treatments. If N was available, N uptake increased when photosynthesis increased. If N was not available, seed N concentration decreased. The data suggest that leaf senescence does not occur because of seed N demand, but may be regulated by processes in the leaf.

Published with the appproval of the Director of the Kentucky Agric. Exp. Stn. as paper no. 94-3-179

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

Copyright © 1995. Crop Science Society of America, Inc.Copyright © 1995 by the Crop Science Society of America, Inc.