Lee, David , Kumar, B. M. , Paliwal, Kailash , Husby, Chad E .
Shade Responses of Seedlings of Five Tree Species from Indian Tropical Seasonal Forests.
Seedlings of five tree species native to seasonally dry tropical forests in India varied in responses to shade, as intensity and spectral quality. We examined seedlings responses of Hopea parviflora (Dipterocarpaceae) native to tropical evergreen forests with a short 1-2 mo dry season, and also. We also studied seedlings of four Terminalia species (Combretaceae), native to deciduous forests with dry seasons up to 8 months duration and distributed throughout India: T. arjuna, T. bellirica, T. chebula and T. tomentosa. Seedlings were grown in shade houses that altered light intensity [photosynthetically active radiation (PAR)] and spectral quality [quantum ratios of radiation at 660 to 730 nm (R:FR)] to produce six treatments: (1) 3% sunlight and R:FR of 0.25, or LFR; (2) 3% sunlight and R:FR of 1.2, or LRR; (3) 12% sunlight and R:FR of 0.25, or MFR; (4) 12% sunlight and R:FR of 1.2, or MRR; (5) 45% sunlight and R:FR of 1.2, or HRR; and (6) direct sunlight and R:FR of 1.2. We measured leaf variables (mass/area, area, petiole length), allocation (biomass of roots, stems and leaves), architecture (height, internode length, degree of branching, stem diameter and mass/length) and calculated leaf area/stem length. PAR and R:FR affected seedling development in a complex manner, affecting species and traits differently, and the directions of responses to reductions in PAR and R:FR. PAR was generally more important than R:FR, and the two light variables interacted in affecting certain variables, suggesting the proximity effects of nearby plants in the high R:FR treatments. Shade responses among the seedlings of these species were not of etiolation, but generally produced seedlings of similar robustness to those of higher light conditions, suggesting trends towards greater persistence, but not explainable in phylogenetic or ecological terms.
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1 - Florida International University, Deparment of Biological Sciences, 11200 SW 8th St., Miami, Florida, 33199, USA
2 - Madurai Kamaraj University, School of Biological Sciences, Madurai, Tamil Nadu, 625 021, India
seedling growth and development
Presentation Type: Oral Paper:Papers for Topics
Location: Stevens 1/Hilton
Date: Tuesday, July 10th, 2007
Time: 10:45 AM