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During photosynthesis, submersed aquatic plant stands create ‘envelopes’ of raised pH and dissolved O2 concentrations and depleted dissolved CO2 concentrations. These may extend beyond the plant stands, suppressing the photosynthetic performance and increasing the photorespiratory stress of adjacent species. In competition between three aquatic macrophytes,(More)
It has been suggested that submerged aquatic plants can influence the nutritional quality of the periphyton which grows on their surfaces, making it more nutritious for grazing invertebrates, particularly snails. In return, these grazers might preferentially feed on the periphyton and clear the plants of a potential competitor, with the plants and grazers(More)
In laboratory experiments, the growth characteristics of the submerged species Elodea nuttallii (Planch.) St. John and Potamogeton crispus L. were assessed in the presence and absence of floating mats of Azolla filiculoides Lam. and Lemna minuta Kunth. Light penetration and the development of pH and dissolved oxygen differences were monitored. The growth of(More)
In slow-moving and static eutrophic waters, submerged macrophytes growing in dense stands produce a highly structured environment, with reduced internal water flow. An afternoon lull in the net photosynthesis of such stands has been reported from a number of previous studies. This has been attributed to increased photorespiration caused by an accumulation(More)
The growth of the shoot and roots of seedling plants of cocoa (Theobroma cacao L.) under constant glasshouse conditions showed a rhythmic cycle, with the maximum growth stages of each alternating in a regular sequence. When the growth cycle of the shoot was upset by removing all new leaves immediately after unfolding, the roots showed a high constant growth(More)
Tissue cultures were initiated from one non-tolerant (S20) and two zinc and lead tolerant (T92 and T94) clones of Anthoxanthum odoratum. Growth of callus from the non-tolerant clone was reduced by the presence of zinc, lead, copper and nickel, whereas callus from the two tolerant clones showed no reduction of growth in the presence of zinc and lead but(More)
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