Mineral nutrition of drosera erythrorhiza with special reference to its tuberous habit
Pate, J.S.; Dixon, K.W.
Australian Journal of Botany 26(4): 455-464
The seasonal cycle of uptake and partitioning of N, P, K, Mg, Na, Ca and Zn by D. erythrorhiza was studied in natural habitat near Perth [Western Australia]. All elements except Ca were mobilized from germinating parent tubers with more than 80% efficiency. The leaf rosette served as the major repository for minerals obtained from the parent tuber and rooting medium. Efficiency of carry-over from vegetative parts to the new season's tubers was 88% for P, 79% for N, 71% for dry matter, 63% for Mg, 56% for K, but only 25-39% for Ca, Na and Zn. Pot culture studies showed insects [Drosophila] to be an effective source of N and P, and eluate of ash particularly a source of K. Habitat soil enriched with whole ash produced tubers especially rich in N, P, Mg and Ca, elevated levels of P being attributed particularly to the ash. Growth on full mineral culture solution or distilled water produced tubers with low levels of minerals. Tuber composition varied greatly between habitats, especially in relation to P, N and Zn. The relationship between P levels in tubers and recent fire history of a habitat was examined.