Consequences of the elimination of old leaves upon spring phenological events and the new leaves nutrient concentration in a wintergreen woody species in the Southern hemisphere

DAMASCOS, MARIA; HENRIQUE, B.; PRADO, A.; LADIO, ANA; ARRIBERE, A. M.; RIVEIRO GUEVARA, S.

PLANT ECOLOGY

Springer

Lugar: The Netherlands; Año: 2005 vol. 181 p. 1 - 8

1385-0237

In previous works the defoliation effects on growth and on new leaves nutrient concentration were analyzed since the early Spring in wintergreen species. However, resources for growth may had been translocated previously in Autumn dissembling the results. In this work the old leaves defoliation effects on Spring new leaves (nutrient concentration and specific leaf mass, SLM, g m-2), on initial shoot growth, and on flowering were studied in a wintergreen species Aristotelia chilensis through Autumn defoliation (AD), early Spring defoliation (SD) and in control plants (CO). The new leaves SLM values were similar in AD (67.22±5.60 g m-2),  SD  (62.55±7.86 g m2),  and in CO (68.8±8.46 g m2) plants. The mineral nutrient concentration (N, P, K, Mg, Mn, Na, and Cl) also did not show a significant decreasing in AD or SD plants. Notwithstanding, the initial growth of flowering shoots was lower in AD (1.95±0.60 cm) or SD (1.05±0.34 cm) than in CO (5.19±1.61 cm) plants. In addition, the non-flowering shoot growth was lower in AD (2.81±1.46 cm) or SD (0.88±0.21 cm) than in CO (5.51±2.81 cm) plants. Furthermore, considering only the flowering plants, Spring defoliation caused significant growth decreasing in non-flowering than in flowering  shoots. Hence, since the end of Summer the old leaves cohort of Aristotelia chilensis is an important carbon source to cover the demand of shoot growth and flowering but the new leaf cohort nutrition and formation seems to be independent and would be assured by the bud preformation since the end of Summer.