Size-specific carbon allocation, seed production, and seed dispersal patterns in a desert lignified annual, Blepharis sindica (Acanthaceae)
2003
Narita, Kenji
Blepharis sindica (Acanthaceae) is a lignified annual plant inhabiting the Thar Desert. It has relatively large seeds (7.8 mg dry mass) and unique structures: lignified stems, spiny hard bracts, and hard, lignified capsular fruits. In order to understand the life history characteristics of this annual and its adaptation to the unpredictable and harsh conditions of the desert environment, resource allocation pattern and dispersal traits were analyzed in relation to plant size. Seed size and/or number may decrease with an increase in allocation to lignified stems, branches, bracts, and capsular fruits. However, these non-seed structures may play important roles with respect to reproductive success in desert environments. Reproductive allocation and seed output (total resources devoted to seeds) decreased and relative allocation to stems increased as plant size increased. Seed size increased rapidly at a certain plant size and held relatively constant above that size. The number of seeds produced did not increase below the critical resource level; however, seed number increased exponentially above this level. Seed dispersal correlated to plant size: larger plants tended to disperse lower proportions of seeds. These results suggest that non-seed maternal efforts in this annual plant are important for the establishment of a seed bank and the regulation of seed dispersal.
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