Stomatal conductance, chlorophyll content, diameter and height in different growth stages of rubber tree (Hevea brasiliensis) saplings

This research reports results from preliminary data collection for carbon sequestration estimation of rubber plantations. The objective of this study is to determine the stomatal conductance, chlorophyll content, diameter and height at different growth stages of rubber tree saplings. Stomatal conductance, chlorophyll content, diameter and height were measured on the rubber tree (Hevea brasiliensis) saplings. The measurements were done in two weeks period on twenty saplings for each of two growth stages, i.e, 45, and 90 days respectively, and seventeenth saplings for growth stage of 135 days. Electronic devices were used to measure stomatal conductance, chlorophyll content and stem diameter, while measurement tape was used to measure the height of the samples to avoid destructive samplings. Results showed that stomatal conductance decreased with increased growth stages of rubber tree saplings. Chlorophyll content was highest at a growth stage of 90 days, followed by 45 days and 135 days. However, for diameter and height, results indicated the increase in both variables with increase growth stages of saplings. ANOVA of stomatal conductance, chlorophyll content, diameter and height within the growth stages of rubber trees saplings were analysed. From the analysis, the means of stomatal conductance, chlorophyll content, diameter and height were found to be significantly different within the growth stages of rubber tree saplings (P≤0.05). Since rubber plantation is one of the major plantations in Malaysia, the findings from this study may be useful as baseline information on the physiology of rubber trees.