Stimulasi pembuangan lima spesies tanaman semak dalam keadaan lingkungan berpolusi dengan menggunakan zat penghambat tumbuh paclobutrazol

Abstract

This research is aimed at finding out the influence of the growth-slowening- substance called paclobutrazol towards the blossoming stimulation of five species of bush planted on polluted street side. It is also aimed at finding out which species that is tollerant to the pollutant, so that in the future it can be recommended to be planted on the street side. The research is carried out both in the streets with heavy traffic and in a greenhouse (the controll subjects). The research design used for the present research is the Random Factorial Group design that consists of 2 treatmen and 3 times of repetitions. The results of the research-show that the content of NO₂ in the bush growing in the streets is 89.53 µg/m³ (0.0477 ppm), whereas the content of SO2 is 3.81 µg/m³ (0.0015 ppm). This is considered to be harmless for the generative growth of the bush because it is still below the standard limit. The content of Pb in Musaenda alba growing both in the streets and in the greenhouse is mostly about 0.059 (µg/cm²) and 0.012 (µg/cm³) respectively. The biggest deposit of Pb occurs on the streets with heavy traffic. The colour of blossoms and leaves of the bush growing in the streets and greenhouse does not show any significant difference. Lantana camara has a very good ability to grow in a polluted surrounding. This is proved by the evidence, in terms of the number of blossoms, that those growing in the streets have 15,2, whereas those growing in the greenhouse have 6,8. Meanwhile, the use of paclobutrazol towards the number of blossoms is 300 ppm. Mussaenda alba growing in the streets have the lowest APTI (Air Pollution Tolerance Index) value, namely 10.20, so that it is categorised as the bush that is very sensitive againts the air pollution caused by motor vehicle's emmision. However, in the greenhouse, it has APTI value of 15.48. Allamanda cathartica, Lantana camara, Ixora javanica growing in the streets have sufficient tollerance against the air pollution, whereas Jatropha gossypifolia is relatively tollerant against the air pollution. In the greenhouse, Allamanda cathartica and Ixora javanica have sufficient tollerance againts the air pollution, whereas Lantana camara, Mussaenda alba and Jatropha gossypifolia are relatively tollerant against the air pollution. The use of paclobutrazol towards the APTI values in the streets is lower than in the greenhouse.