Root mass distribution patterns under standardised conditions in species of Chionochloa and Festuca from New Zealand

Abstract

The vertical biomass allocation patterns of roots grown under standardised conditions were determined for species representing the major New Zealand indigenous grass genera Chionochloa and Festuca. Ten ramets, each of 2–3 tillers from garden collections of each species were grown in irrigated vertical sand columns in a glasshouse, and harvested after 168days. Chionochloa teretifolia, Chionochloa macra, and Chionochloa crassiusucula, characteristic of alpine environments failed to produce new roots and died. However, most of the Chionochloa taxa (Chionochloa beddiei, Chionochloa pallens, Chionochloa rigida ssp. rigida, Chionochloa rubra ssp. cuprea, Chionochloa vireta), developed extensive new roots that reached the base of the one metre sand column. Roots of Chionochloa cheesemanii and Chionochloa conspicua reached 80–90cm depth. Two Festuca taxa (Festuca actae, Festuca luciarum) had roots to 1m depth, and roots of Festuca coxii, Festuca matthewsii ssp. latifundii, Festuca matthewsii ssp. matthewsii, Festuca multinodis, and Festuca novae-zelandiae grew to 70–90cm depth. The edaphic specialists (Festuca deflexa, Chionochloa spiralis, Chionochloa defracta) were all shallow rooting.Species of Festuca maintained at least 40% of the root mass in the upper 10cm of the column and most of the Chionochloa taxa had less than 40% of root mass in the upper zone. Genotype level variation in root mass less than 10cm deep was greater in Chionochloa than in Festuca, and least in the edaphic specialist grasses.