PENGARUH WAKTU PEMBERIAN DAN KONSENTRASI PACLOBUTRAZOL TERHADAP PERLAMBATAN PERTUMBUHAN TREMBESI (Albizia saman Jacq)

The aims of this study was to determine the effect of spraying time and concentration of paclobutrazol on the growth rain tree seedlings (Albizia saman, Jacq). Rain tree has advantage by absorbing CO2 from the atmosphere in large quantities. The disadvantage is that size of the tree is large so it needs to be done to slowly or inhibit growth can be planted in small narrow garden. The experiment was carried out in the experimental farm Faculty of Agriculture, Universitas Islam Riau, Air Dingin Village, Bukit Raya District, Pekanbaru Riau Indonesia from March to June 2020. This research has been carried out experimentally using a completely randomized design consisting of two factors and three replications. The first factor is spraying time which is divided into three levels. The second one is the concentration of paclobutrazol, consisting of four levels. The results showed that could slow plant height up to 54.67%. Increase in the size diameter stem at 50 days and 75 days with concentration 150 ppm with stem diameter of 0.94 cm and 0.92 cm, respectively. Emphasis on the number primary branches at 50 days treatment and a concentration of 150 ppm which only produced 17.58 branches. The number of leaves also decreased by 72.83 leaves compared to the control, which was 91.92 leaves. The chlorophyll content showed the highest diversity in the control