Growth response of Bolboschoenus maritimus ssp. maritimus and B. maritimus ssp. compactus to different trophic conditions

Bolboschoenus maritimus (L.) Palla (=Scirpus maritimus L.) forms extensive stands in the littoral zone of small fishponds and as a weed in rice and maize fields. Within the species, two subspecies are distinguished: Bolboschoenus maritimus subsp. maritimus, B. maritimus subsp. compactus. They differ in ecology, especially in their relationships with trophic conditions and salinity of habitats. To determine growth response of these two types to different nutrient levels, we compared their seasonal development under experimental cultivation at four controlled nutrient levels. Some differences between the subspecies were found to be stable, regardless of nutrient level, namely greater amount of smaller underground tubers and more extensive rhizome system in subsp. compactus compared to less numerous larger tubers and simpler rhizome system in subsp. maritimus. In response to trophic conditions,the plants of subsp. compactus were more resistant to the conditions of the highest trophic level than those of subsp. maritimus, which were stressed. This demonstrates better adaptability and spreading ability of B. maritimus subsp. compactus at high trophic levels.