Provenance variation on morphologic, anatomical and physiological characteristics of Casuarina equisetifolia grown at Lad Krating Plantation, Chachoengsao

Objectives of the present study were aimed to determine variation on morphological, anatomical and physiological characteristics of ironwood (Casuarinaequisetifolia) grown at Lad Krating Plantation, Chachoengsao. It was also aimed to provide information on growth for future applications. Highly significant differences in seed length, seed width and seed weight of 28 ironwood provenances were found. The average survival percentage of the 36 months old ironwood was 63.96 percent, ranging from 35.42 to 86.11 percent. Significant differences in height, diameter at 10 cm from ground level and diameter at breast height among provenances of ironwood at all ages were observed. Average height of ironwood at 6, 12, 18, 24, 30 and 36 months were 2.0, 3.22, 4.77, 6.46, 7.19 and 8.83 m respectively. Mean diameters at 10 cm from ground level of ironwood were 1.79, 3.13, 5.07, 6.38, 7.11 and 8.11 cm respectively while mean diameters at breast height of 12, 18, 24, 30 and 36 months old were 1.65, 3.37, 4.58, 5.24 and 6.29 cm respectively. At all ages studied, the provenance group from East Asia had the best average growth performance but they were not cleared where were the origins of these seed sources. Thus, the best provenance to be selected for Lad Krating Plantation should be the Thai provenance either from Had Chao Mai, Trung or Rahu. There were no differences in branchlet anatomy among 13 selected provenances of ironwood. This was due to the branchlets of ironwood, which were found to be furrowed. Numerous stomata, consisting of guard cells, subsidiary cells, and pores, were located between the ridges, mostly on the flank of the furrows. The stomatal pattern was of the paracytic type. More stomata were found on the middle part of the segment of the branchlet. Highly significant differences in stomatal frequency and stomatal length were found among 13 provenances of ironwood. Ironwood branchlet area was found to be significantly correlated with basal area of subsidiary branch. The relationships between these characters were linear regression. In determining the photosynthetic rate of ironwood, highly significant differences in photosynthetic rate between 9.30-11.00 am among 13 provenances were found. The inclination of diurnal photosynthetic rate of ironwood did not clearly followed the trend of irradiance during the day.