PENGARUH CEKAMAN KURANG AIR TERHADAP BEBERAPA KARAKTER FISIOLOGIS TANAMAN NILAM (Pogostemon cablin Benth)

ABSTRAKNilam (Pogostemon cablin Benth) merupakan salah satu tanamanpenghasil minyak atsiri yang dikenal dengan minyak nilam (patchouli oil).Salah satu kendala dalam pengembangan tanaman nilam adalah pekaterhadap kekurangan air. Perubahan iklim cenderung menyebabkan lebihsering terjadi kekeringan di sejumlah wilayah termasuk Indonesia sehinggadalam pengembangan tanaman nilam diperlukan varietas toleran terhadapcekaman kurang air. Terdapat tiga varietas unggul nilam (Tapaktuan,Sidikalang, dan Lhokseumawe) dengan produksi minyak (290-375 kg/ha)dengan kadar patchouli alkohol 32–33%. Penelitian bertujuan untukmengevaluasi respon fisiologis 4 varietas/aksesi tanaman nilam terhadapcekaman kurang air. Penelitian dilaksanakan di rumah kaca di Bogor padatahun 2012. Penelitian menggunakan RAK faktorial dengan tiga ulangan.Faktor pertama 4 varietas/aksesi nilam (V) yaitu Sidikalang,Lhokseumawe, Tapaktuan, dan Bio-4. Faktor kedua empat intervalpenyiraman (W) yaitu 1, 3, 6, dan 9 hari sekali. Evaluasi pengaruhcekaman kurang air dilakukan terhadap beberapa karakter fisiologitanaman nilam. Pengamatan dilakukan antara lain terhadap peubah kadarlengas tanah, konduktivitas stomata (Gs), laju transpirasi (Tr), kandunganair nisbi (KAN), potensial air daun (PAD) dan kandungan prolin daun.Hasil penelitian menunjukkan bahwa terjadi penurunan kadar lengas tanah,konduktivitas stomata, laju transpirasi, dan KAN pada semua varietas,sedangkan PAD dan kadar prolin meningkat seiring dengan semakinlamanya interval penyiraman. Kadar prolin tertinggi pada interval 9 harisekali pada varietas Sidikalang. Tidak terdapat perbedaan responvarietas/aksesi nilam yang diuji.Kata kunci: Pogostemon cablin Benth, cekaman kurang air, karakterfisiologis.ABSTRACTPatchouli (Pogostemon cablin Benth) is one of plant that producespatchouli oil call patchouli oil. However, patchouli is susceptible todrought. The effect of global warming which changes rainfall patterncaused droughts in several regions including Indonesia. Therefore, it isimportant to find patchouli variety which is relatively tolerant to drought.Tapaktuan, Sidikalang, dan Lhokseumawe are three varieties of patchouliwhich produce high essential oil (290-375 kg/ha) with high patchoulialcohol content (32–33%). The objective of this research was to evaluatethe physiological responses of four varieties/clone of patchouli to drought.The experiment was conducted at greenhouse at Cimanggu, Bogor fromFebruary to July 2012. The research was designed in randomized factorialblock design (RBD) with three replications. The first factor was fourvarieties/clone of patchouli (V) Sidikalang, Lhokseumawe, Tapaktuan, andBio-4. The second factor was four watering intervals (W) every 1, 3, 6and 9 days of watering. Parameters evaluated were physiologicalcharacteristics, soil moisture content, stomatal conductance, transpirationrate (Tr), leaf water potential, relative water content, and proline content ofleaf. The results showed that soil moisture content, stomatal conductivity,transpiration rate and relative water content decreased, while leaf waterpotential and proline levels increased along with the increase of wateringintervals. The highest proline level was at interval of nine days wateringtreatment on Sidikalang varieties. However, all varieties/clone have notdifferent responses to water deficit.Key words: Pogostemon cablin Benth,water deficit, physiologicalcharacteristic