Influence of Boll Removal on Assimilate Partitioning in Cotton¹

Abstract

Field experiments with Upland cotton (Gossypium hirsutum L.) were initiated to determine the effect of boll removal on the distribution of 14C‐assimilates 24 hours following removal. The mainstem leaf subtending the sympodium supplied the first and second boll positions with assimilates. In the absence of bolls, assimilates in the mainstem leaf moved basipetally from the leaf subtending the first position. The majority of assimilates were translocated to the first position boll. Removal of the first position boll resulted in assimilate movement to the second position parts of the plant when the second position was 10 days old. The majority of the assimilates from the second position leaf, being further out on the sympodium, remained in the sympodium, as long as at least one fruiting body was present. Removal of all the bolls from the sympodium resulted in translocation primarily in a basipetal direction.

Path coefficient analysis to assess yield losses due to a multiple pest complex in cotton in Thailand

“…The second one was retained as plants in Group B, being planted early, benefited from better hydric conditions, i.e. more favourable conditions for compensation, than Group A (Hearn and Room, 1979;Peoples and Matthews, 1981).…”

“…Entomologists often emphasize the population dynamics and pest feeding habits rather than plant compensation processes (Wilson and Waite, 1982;Zadoks, 1985;Boote et al, 1993). Physiologists have analysed the effects of artificial injuries by reducing leaf area or number of fruiting organs but have seldom studied the interaction between these two types of injuries or the impact of cumulative injuries on further pest dynamics (Peoples and Matthews, 1981;Mutsaers, 1983;Ungar et al, 1987).…”

Photosynthetic and Respiratory Activity of Fruiting Forms within the Cotton Canopy

“…The supply of photosynthate for fruit development in cotton (Gossypium hirsutum L.) requires the contribution of assimilate from several sources (2,4,5,20). Studies have shown that the major suppliers of carbon for fruit development are the leaf subtending the boll, the leaf subtending the adjacent fruiting position, and the leaf subtending the sympodium (14).…”

“…Labeled 14C02 injected into the fruit interior was rapidly assimilated by the capsule wall in the light but not in the dark, while fiber and seed together fixed significant amounts of 14C02 in both the light and dark. These data suggest that cotton fruiting forms, although sites of significant respiratory CO2 loss, do serve a vital role in the recycling of internal CO2 and therein, function as important sources of assimilate for reproductive development.The supply of photosynthate for fruit development in cotton (Gossypium hirsutum L.) requires the contribution of assimilate from several sources (2,4,5,20). Studies have shown that the major suppliers of carbon for fruit development are the leaf subtending the boll, the leaf subtending the adjacent fruiting position, and the leaf subtending the sympodium (14).…”

Response of Upland Cotton (Gossypium hirsutum) to Fruiting Branch Removal

“…The removal of fruiting branches in this study caused not only defoliation, but also loss of reproductive structures such as squares, flowers and bolls. The loss of fruit structures in cotton plants increases the photosynthetic capacity and nitrogen assimilation, changes the source–sink balance, distribution of photo‐assimilates and spatial fruiting pattern, as well as delays fruit setting (Peoples and Matthews 1981, Sadras 1996, Wells 2001, Dumka et al. 2003).…”