Canarium odontophyllum is a rare tropical fruit that is primarily propagated by seeds.
However, there is little information regarding its seed handling and germination. As
low seed moisture content (MC), generally that below 10%, is the key determinant to
successful seed storage while avoiding microbial damage, the objective of this study
was, hence, set to investigate C. odontophyllum’s seed germination as affected by
desiccation using drying beads (DBs) at room temperature or convection oven at
40C to varying seed MCs, from its initial MC of above 20% down to that below 10%.
It was found that the seeds tolerated fast dehydration within 24h at room temperature
using DBs. They retained 90% germination despite seed MC was reduced to below
10%. Desiccation tolerance with DBs was, however, found only with seeds extracted
from fresh fruits. As the fruits started rotting with wrinkled appearance and fungi on
the pericarp from four days after harvest onwards, the seeds extracted from them died
at MC of below 15%. A slower seed drying method using convection oven at higher
temperature of 40C, on the other hand, took 72h to bring the seed MC down to
Syzygium myrtifolium (Roxb.) Walp. is a popular landscape plant in Malaysia. This species is always planted as hedge plant and topiary. However, it requires frequent trimming to maintain its form and aesthetic functions as it grows vigorously. Conventional trimming technique by using trimming shear or trimming machine is currently practiced in landscape maintenance which is time consuming, labour intensive and costly. Therefore, a study was conducted to investigate the effects of a plant growth retardant, paclobutrazol, on the growth and physiological response of S. myrtifolium. The plants were planted in polyethylene bags sized 33 cm in height × 27 cm in diameter and filled with soil, organic matter and sand (3:2:1). Paclobutrazol at rates of 0, 1.25, 2.50 and 3.75 g L-1 were soil drenched at 30 days after the plants were trimmed and new shoots were produced. Paclobutrazol significantly reduced plant height and leaf area but increased the leaf area index. Reduced photosynthetic rates were recorded with the treated plants as compared to the control plants. In addition, paclobutrazol at 3.75 g L-1 significantly reduced the transpiration rate as compared with the control plants and plants treated with 1.25 g L-1 of paclobutrazol. However, stomatal conductance was not affected significantly by paclobutrazol. The growth inhibition effect of paclobutrazol reduced the trimming activity in S. myrtifolium. Chlorophyll fluorescence measurement indicated that physiological processes in the paclobutrazol-treated plants were not affected. Paclobutrazol is concluded to offer a better approach in maintaining the growth of S. myrtifolium.
This research aims to determine growth and deficiency patterns as well as antioxidative potentials of Japanese mint (Mentha arvensis) hydroponically grown under limited macronutrients and micronutrients. The experiment was conducted for 60 days after transplanting in an evaporative greenhouse (avg temp = 28-30 °C, 60-65 %RH), using deep water culture technique. Plants were grown in nutrient solution consisting of complete Hoagland's solution (CTRL), and nutrient solutions lacking one of the following macronutrients and micronutrients: nitrogen (-N), phosphorus (-P), potassium (-K), iron (-Fe), manganese (-Mn), and copper (-Cu). The deficiency symptoms, growth patterns, and stress response mechanism were followed. All treatments except for the CTRL induced deficiency symptoms and physiological changes. Macronutrient deprivation reduced growth determined by the morphological parameters while micronutrient omission had no effect except for no iron treatment. The result showed that potassium and iron deficiencies had foremost adversely effect on growth of Japanese mint. Under nutrient stress conditions, plant only gave antioxidative responses to phosphorus and potassium deficiencies. However, the negative plant-stress relationship was found for no iron treatment indicating the detoxification mode of plant for lacking of micronutrient.