Limits to the height growth of Caragana korshinskii resprouts

X. Fang, Neil Turner, D. Xu, Y. Jin, J. He, Feng-min Li

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9 Citations (Scopus)

Abstract

Predawn leaf water potential (LWP), the LWP between 09:00 and 10:30 h (termed minimum LWP), stem xylem hydraulic conductivity, foliar nitrogen, leaf gas exchange and leaf traits were measured on the same days in adults and 1-year-old to 7-year-old resprouts that had regrown after removing all the aboveground shoots. Height growth and accumulation of aboveground biomass quickly decreased with resprout age and there was no difference between 7-year-old resprouts and the uncut adults. Predawn LWP showed no significant difference between resprouts and adults, but the minimum LWP decreased gradually from -2.0 MPa in 1-year-old resprouts to -3.0 MPa in 7-year-old resprouts. The decrease in minimum LWP was associated with increased hydraulic resistance, as indicated by the gradual decrease in leaf area-specific hydraulic conductivity (KL) and sapwood area-specific hydraulic conductivity (KS) and the associated increase in stem native percentage loss of hydraulic conductivity in older than 2-year-old resprouts. The leaf nitrogen content per unit area (Narea) also decreased steadily from 3.6 g m-2 in 1-year-old resprouts to 1.7 g m-2 in 7-year-old resprouts. With the decline in LWP and Narea, the rate of leaf photosynthesis per unit area (Aarea) decreased from 20 μ mol m-2 s -1 in 1-year-old resprouts to 11 μ mol m-2 s -1 in 7-year-old resprouts. In adults, although KS decreased further compared with 7-year-old resprouts, the minimum LWP, K L, Narea and the rate of photosynthesis increased by 0.3 MPa, 29, 34 and 23%, respectively. The results show that a progressive loss of stem hydraulic conductivity and a steady decrease in foliar nitrogen with age were associated with a decrease in the photosynthetic rate of Caragana korshinskii Kom. resprouts, possibly changing the allocation of photosynthetic assimilates and slowing resprout height growth. © 2013 The Author.
Original languageEnglish
Pages (from-to)275-284
JournalTree Physiology
Volume33
Issue number3
DOIs
Publication statusPublished - 2013

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