Changes in dry matter, carbohydrate and seed yield resulting from lodging in three temperate grass species
2000
Griffith, S.M.
The adverse effect of lodging on grass seed yield may be attributed, in part, to assimilate limitation during the seed filling period. This investigation examined plant dry matter assimilate partitioning and seed yield as affected by lodging in three species that are closely related but phenotypically different: tall fescue (Festuca arundinacea Schreber.), Italian ryegrass (Lolium multiflorum Lam.), and perennial ryegrass (L. perenne L.). Studies were performed in field plots at Corvallis, Oregon, USA. Seed yield components (seed number per inflorescence, seed yield per inflorescence, and single seed mass) and leaf, stem (lower, middle, and peduncle) and seed inflorescence dry mass were measured just prior to anthesis to seed maturity. Dry mass and water soluble carbohydrates (WSC) were determined for shoot components. The reduction in dry mass and WSC in leaves and stem components following anthesis was often greater in lodged plants compared to upright plants. The relatively low seed yield depression in lodged tall fescue suggested a higher compensation potential for partitioning reserve assimilate from leaves and stems to support seed growth and development. This potential does not appear to be present to the same degree in Italian ryegrass and to an even lesser extent in perennial ryegrass. These findings suggest that the potential to compensate for reduced assimilate supply during the period of high assimilate demand by seeds may be attributed, in part, to the total assimilate reserve accumulated prior to photoassimilate reduction caused by the lodged condition.
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