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White Clover Morphology and Physiology in Response to Defoliation Interval
Author(s) -
Kang J. H.,
Brink G. E.
Publication year - 1995
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci1995.0011183x003500010048x
Subject(s) - stolon , trifolium repens , biology , leaf size , cultivar , forage , sowing , agronomy , dry matter , specific leaf area , biomass partitioning , botany , biomass (ecology) , photosynthesis
Yield response of white clover ( Trifolium repens L.) to defoliation varies with leaf size. Our objective was to determine how specific aspects of plant morphology and physiology are responsible for differences in growth of diverse white clover cultivars in response to defoliation interval. Individual plants of ‘Aberystwyth S184’ (small‐leaf), ‘Grasslands Huia’ (medium‐smali‐leaf), and ‘Osceola’ (large‐leaf) were clipped to remove all fully expanded leaves and petioles 55 d after sowing in the greenhouse and then clipped every 7, 14, or 28 d for the next 28 d. Plant fraction dry matter (DM) accumulation and morphological and physiological characteristics were measured 1, 3, 7, 14, and 28 d after the final clipping. Stolon growth rate was inverse to leaf size classification (Aberystwyth S184, 7.6 cm d −1 Grasslands Huia, 5.8 cm d −1 > Osceola, 3.6 cm d −1 ). In contrast, maximum stolon weight/length ratio of Osceola increased 31% vs. a 1% increase for Grasslands Hula and Aberystwyth S184 as defoliation interval increased to 28 d, which resulted in greater stolon DM accumulation by Osceola at the 14‐ and 28‐d intervals. Stolon and root carbohydrate concentration of Osceola was greater than and leaf carbohydrate concentration was less than the other cultivars at all defoliation intervals, indicating greater reliance on stored carbohydrates for regrowth by Osceola. Although plant leaf area of Oseeola was greater than that of Grasslands Hula and Aberystwyth S184 at the 28‐d interval only, forage DM accumulation of Osceola was greatest at all intervals due to petiole length. In grazed swards, however, greater petiole length would likely increase accessibility to and removal of leaf tissue, subsequently reducing new leaf and stolon growth.