Effect of airflow and carbon dioxide on growth, yield, and gas exchange of lettuce
Chen, Guang-Yau Stanley
This item is only available for download by members of the University of Illinois community. Students, faculty, and staff at the U of I may log in with your NetID and password to view the item. If you are trying to access an Illinois-restricted dissertation or thesis, you can request a copy through your library's Inter-Library Loan office or purchase a copy directly from ProQuest.
Permalink
https://hdl.handle.net/2142/21203
Description
Title
Effect of airflow and carbon dioxide on growth, yield, and gas exchange of lettuce
Author(s)
Chen, Guang-Yau Stanley
Issue Date
1996
Doctoral Committee Chair(s)
Spomer, L. Art
Department of Study
Crop Sciences
Discipline
Crop Sciences
Degree Granting Institution
University of Illinois at Urbana-Champaign
Degree Name
Ph.D.
Degree Level
Dissertation
Keyword(s)
Agriculture, Agronomy
Biology, Plant Physiology
Language
eng
Abstract
Romaine lettuce (Lactuca sativa var. longifolia L.) was grown hydroponically inside a walk-in growth chamber (Conviron, PGW36) with two levels of airflow (0.36 and 2.50 m$\rm\cdot s\sp{-1})$ at different atmospheric CO$\sb2$ concentrations (350 and 700 $\rm\mu mol\cdot mol\sp{-1}).$ A combination of metal-halide and high-pressure sodium lamps was used to provide 30 mol$\rm\cdot m\sp{-2}$ photosynthetic photon flux (PPF) per day with a 12-hour photoperiod at the rate of 660 $\rm\mu mol\cdot m\sp{-2}\cdot s\sp{-1}.$ Air temperature was maintained at 22$\sp\circ$C and relative humidity at 70% for both day and night. Nutrient solution pH was kept at 5.7 with nitrate as the sole nitrogen source. Growth analysis was carried out at 3-day intervals and gas exchange rate of both single-leaf and whole-plant was measured with a modified portable photosynthesis system (LI-COR, LI-6200 PPS). A microcomputer-based data acquisition and process control system was developed to maintain CO$\sb2$ concentration and monitor environmental condition in each of the four runs of this experiment.
Results from this study indicated that CO$\sb2$-enhancement can greatly increase the growth and yield of lettuce by increasing RGR shortly (1.3 days) after the treatment was applied. It created bigger plants while it kept them at the same physiological age with equal leaf number per plant as those grown under low CO$\sb2$ environment. In contrast, higher airflow decreased lettuce yields by producing smaller plants with fewer leaves per plant than under lower airflow. The delay of growth and development caused by higher airflow was estimated to be 1.3 days, while RGR remained the same throughout the rest of growth.
The results of this study confirm that airflow is an important environmental factor, which should be controlled or characterized in every experiment. There should exist an optimal range of airflow for plants growing under unique environments. In order to promote the maximum crop growth and yield under a particular controlled environment, the timing and duration of CO$\sb2$-enrichment and control of airflow need to be considered.
Use this login method if you
don't
have an
@illinois.edu
email address.
(Oops, I do have one)
IDEALS migrated to a new platform on June 23, 2022. If you created
your account prior to this date, you will have to reset your password
using the forgot-password link below.
