EFFECTS OF PACLOBUTRAZOL ON THE GROWTH AND ANATOMY OF STEMS AND LEAVES OF SYZYGIUM CAMPANULATUM

A study was conducted to determine the effects of paclobutrazol on plant height and leaf area of Syzygium campanulatum. The height of paclobutrazol-treated (1.25, 2.50 and 3.75 g l⁻¹) plants was found to be inhibited compared with non-treated plants. The treated plants had smaller leaves compared with those of non-treated plants, one month after treatment. However, there was no difference in plant height and leaf area between plants treated with different rates of paclobutrazol. Scanning electron micrographs of stems showed reduction in xylem thickness, while in the leaves, palisade and spongy parenchyma cells were more closely arranged in response to paclobutrazol. There was also an increase in palisade thickness of leaves of plants treated with 3.75 g l⁻¹ paclobutrazol. Paclobutrazol was found to effectively inhibit plant height and leaf expansion and alter the stem and leaf anatomy of S. campanulatum. Kajian dijalankan untuk mengenal pasti kesan paklobutrazol terhadap ketinggian dan luas daun pokok Syzygium campanulatum. Pertumbuhan pokok yang dirawat dengan paklobutrazol (1.25, 2.50 dan 3.75 g l⁻¹) direncat berbanding dengan pokok kawalan didapati bertambah. Sebulan selepas rawatan, pokok yang dirawat mempunyai saiz daun yang lebih kecil berbanding dengan saiz daun pokok kawalan. Bagaimanapun, tiada perbezaan ketinggian pokok dan luas daun diperhatikan antara pokok yang dirawat dengan kepekatan paklobutrazol yang berlainan. Mikrograf imbasan elektron menunjukkan penurunan ketebalan xilem, manakala di dalam daun, sel mesofil palisad dan mesoni span didapati tersusun secara padat akibat perencatan paklobutrazol. Sel mesofil palisad pokok yang dirawat dengan 3.75 g l⁻¹ paklobutrazol didapati meningkat. Paklobutrazol didapati berkesan merencat ketinggian pokok serta perkembangan daun, dan seterusnya menyebabkan perubahan anatomi batang dan daun pokok S. campanulatum.