The photosynthetic eco-physiological adaptability of the endangered plant Tetracentron sinense to different habitats and altitudes

Tetracentron sinense Oliv, the only tall deciduous tree in family Tetracentraceae, is listed as a national second-grade key protected plant China. To reveal effect of associated species, irradiance, and altitudes on photosynthetic capacity T. sinense, physiological characteristics its species Acer pictum Pterocarya stenoptera were measured by Li-6400 portable meter. The light saturation point (LSP), maximum net rate PN-PAR (PNmax), carboxylation efficiency (CE), PN-CO2 (P*Nmax), carbon dioxide compensation (CCP) respiration (Rp) forest gap (FG) higher than those edge (FE) understory (US). In FE, (PN), (LCP), LSP, P*Nmax lower stenoptera, while PNmax, (Ciast) US stenoptera. specific leaf area (SLA) decreased with reduction irradiance. With increasing altitude, SLA young individuals (YT) increased; LCP YT or LSP mature (MT) increased first then decreased. results showed that 1) adaptability better FG FE US; 2) was weaker ecological range adaptation also narrower placing at competitive disadvantage, which may be one important reasons for poor regeneration; 3) environmental conditions altitude can contribute to growth survival sinense. Therefore, active artificial intervention should undertaken expand transplant seedlings promote population regeneration