Studies on growth of young oak trees as affected by the environment, in particular photoperiod, temperature and also gibberellic acid application
Author(s)
Rendle, Elizabeth L.
Abstract
The effects of three environments (field, tube shelter, glasshouse), gibberellic acid application and continuous illumination on the growth of young oak trees were examined in a factorial experiment over two growing seasons. Both spot measurements and a computer based data-logging system were employed to monitor levels of environmental factors (light intensity, air temperature, CO2, concentration, relative humidity) throughout to determine conditions within each environment, and relationships were derived to link with standard Meteorological data. The tube environment was associated with reduced light intensity, increased temperature and very high humidities. All these factors combined to increase growth in length. Photosynthesis and respiration are affected by increased temperature and decreased light but there was no overall effect on dry matter production. High humidity must reduce transpiration in the tube conditions. CO2" levels in the lower part of the tube were enhanced by CO2" derived from the soil, but very low levels occurred higher up in the tube. The main effect of tube conditions appeared to be in a re-distribution of dry matter within the tree in favour of the shoot. The tube also physically restricts the tree and protects it from wind, these factors must affect growth but are difficult to quantify. Glasshouse environment had higher day and night temperatures than in the field, humidity was similar, but light intensity was slightly reduced. With the easy application of extended daylength the glasshouse can be used to produce larger container-grown seedlings all year round. GA3, application increased height growth in both the tube and glasshouse. In the latter environment GA3, application in combination with 24 hour light did not increase height above the maximum attained in 24 hour light alone. In field conditions the plants remained small with the highest proportion of dry matter in the form of roots.
Version
Open Access
Date Awarded
1988
Copyright Statement
Attribution-Non Commercial-No Derivatives 4.0 International Licence (CC BY-NC-ND)
License URL
Advisor
Schwabe
Sponsor
Forestry Commission.
Publisher Department
Department of Life Sciences
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)