Optimasi Metode Sterilisasi Eksplan dan Konsentrasi Zat Pengatur Tumbuh (ZPT) pada Kultur Tanaman Etlingera elatior (Jack) R.M. Smith sebagai Model dalam Upaya Konservasi Etlingera balikpapanensis A.D. Poulsen = Optimization of Explant Sterilization Method and Plant Growth Regulators (PGR) Concentration in Etlingera elatior (Jack) R.M. Smith Plant Culture as a Model in Conservation Efforts of Etlingera balikpapanensis A.D. Poulsen