Seasonal and diurnal variations of photosynthesis of dendrobium orchid under commercial production in Thailand

Name: Duangporn Boonchai

LCSH: Kasetsart University -- Dissertations. Ph.D. (Tropical Agriculture) 2017

Classification :.LCCS: SB409.8.D45

LCSH: Kasetsart University. Faculty of Agriculture -- Dissertations

LCSH: Dendrobium

LCSH: Dendrobium -- Production

LCSH: Orchid culture

LCSH: Photosynthesis

Abstract: Thailand is the world’s largest exporter of Dendrobium orchid cut-flowers, especially Dendrobium Sonia ‘BOM Jo’ and Dendrobium ‘Khao Sanan’. The commercial scale production system is unique in that orchids are grown on a coconut husk box and raised benches under a 50% shade net house. The environmental conditions for Dendrobium orchids growing under commercial production year-round were monitored at Thaiorchids Company, Damnoen Saduak, Ratchaburi Province, Thailand (lat. 13º 30’N, long 99º 54’E) from 2010- 2011. The average temperature during the daytime was 29.2-36.2ºC, nighttime was 21.6- 27.6ºC, and the difference between day and night was 5.5-9.1ºC. The average air humidity was 56.9-74.4% and 86.1-91.4% during the day and night, respectively. The day length was 12±0.5 hours (6:00-18:00) and light intensity during the summer was higher 2 folds than the other seasons. All the photosynthetic parameters of two cultivars, i.e. CO2 exchange rate (CER), stomatal conductance (gs), transpiration rate (E) and CAM acidity during the year were identified as obligate CAM. This process was divided into 3 phases; Phase I: 18:00- 6:00, Phase II: 6:00-8:00 (exception for winter, it was extended about 2 hours), and Phase III: 8:00-18:00. Phase IV was not found. The highest values of total CO2 balance and malic acid accumulation were found in winter, and were 2-folds higher than in summer. The CER and gs of the two cultivars were correlated with temperature, RH, light intensity and VPD. Both the CER and the gs were positive values during 22-28oC, 60-90% RH, < 1.5 kPa VPD and < 200 µmol m-2 s -1 PPFD. In the beginning of phase I, the CER was correlated with the gs , and gs related to VPD in Den. Sonia ‘BOM Jo’, while Den. ‘Khao Sanan’, CER correlated with temperature and RH as well as gs related to PPFD. Consequently, the Dendrobium orchid growers can adjust or maintain the temperature and RH under a shade net house during 6:00- 9:00 and 16:00-18:00 at about 25-28oC and > 65% RH in order to achieve the highest efficiency of photosynthesis. Therefore, water and fertilizer should be applied during the late afternoon or the early morning when stomata are opening. The results of this study contribute to improving the ability to efficiently design and manipulate the semi-controlled greenhouse for Dendrobium orchid commercial scale production in Thailand.

Kasetsart University. Office of the University Library

Address: Bangkok

Email: tdckulib@ku.ac.th

Name: Patchareeya Boonkorkaew

Role: Thesis Advisor

Name: Poonpipoe Kasemsap

Role: Thesis Co-Advisor

Created: 2017

Modified: 2023-06-16

Issued: 2023-06-16

วิทยานิพนธ์/Thesis

application/pdf

URL: https://kasetsart.idm.oclc.org/login?url=https://www.lib.ku.ac.th/KUthesis/2560/duangporn-boo-all.pdf

CallNumber: SB409.8.D45.D83

eng

DegreeName: Doctor of Philosophy

Level: Doctoral Degree

Descipline: Tropical Agriculture

Grantor: Kasetsart University

©copyrights Kasetsart University

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