Fertilization reduced stomatal conductance but not photosynthesis of Pinus taeda which compensated for lower water availability in regards to growth

FOREST ECOLOGY AND MANAGEMENT

卷:381

Article

Maggard, Adam O.¹  Will, Rodney E.¹  Wilson, Duncan S.²  Meek, Cassandra R.¹  Vogel, Jason G.^3,4 

[1] Oklahoma State Univ, Dept Nat Resource Ecol & Management, Stillwater, OK 74078 USA

[2] Univ Oklahoma, South Cent Climate Sci Ctr, Norman, OK 73019 USA

[3] Texas A&M Univ, Dept Ecosyst Sci & Management, College Stn, TX 77843 USA

[4] Univ Florida, Sch Forest Resources & Conservat, Gainesville, FL 32611 USA

关键词: Leaf gas exchange;    Throughfall reduction;    Fertilization;    Pinus taeda;    Loblolly pine;   

DOI  :  10.1016/j.foreco.2016.08.046

来源: Elsevier

【 摘 要 】

Loblolly pine (Pinus taeda L) is the most commercially important tree species in the southeastern USA. Projected increases in regional temperature and drought severity likely will cause reductions in productivity, in particular for the western edge of the loblolly pine range. To determine the effects of nutrient availability and reduced water availability on leaf gas exchange, leaf area index (LAI), and tree growth, we examined the interactive effects of fertilization (one time application of 224 kg N 28 kg P ha(-1), 56 kg K ha(-1) and micronutrients) and reduced throughfall (approximate 30% reduction) over growing seasons 5-7 for a loblolly pine plantation in southeastern Oklahoma. Throughfall reduction reduced volumetric soil water content from 11.3% to 8.8% and fertilization increased foliar nitrogen concentration from 1.13 to 1.27 mg g(-1). Fertilization increased LAI (10%) and subsequently tree growth while reducing stomatal conductance (7%) but caused less negative (3%) midday leaf water potential. Throughfall reduction reduced stomatal conductance (12%) and net photosynthesis (9%) and these responses were related to more negative midday leaf water potentials (11%). These results indicate that fertilization increased water use efficiency in that fertilized treatments maintained similar net photosynthetic rates as nonfertilized treatments even though stomatal conductance was lower. The net effect was that fertilization increased growth of throughfall reduction treatments such that productivity was similar to ambient throughfall treatments not receiving fertilization. (C) 2016 Elsevier B.V. All rights reserved.

【 授权许可】

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