Variasi Karakter Pembungaan Antar Varian dan Ras Lahan Cendana Sepanjang Gradien Geografis di Gunung Sewu
Authors: Cahyaningrum Yeni Widyana Nurcahyani , Indrioko Sapto , Faridah Eny , Syahbudin Atus 
Published: September 2017

Cendana merupakan spesies asli Indonesia bagian timur, yang menjadi ras lahan di Gunung Sewu. Sembilan ras lahan di Gunung Sewu, seluruhnya tersusun atas tiga varian yang berbeda struktur dan warna bunganya (MK, merah kecil; MB, merah besar; dan KB, kuning besar). Penelitian ini bertujuan untuk menganalisis karakter pembungaan ketiga varian cendana di Gunung Sewu pada periode pembungaan tahun 2015; di tiga ras lahan yang mewakili tiap zona yaitu Nglanggeran (Zona Utara), Bleberan (Zona Tengah), dan Petir (Zona Selatan). Observasi meliputi fenologi, kemasakan organ reproduksi, display, dan struktur pembungaan. Struktur pembungaan dan longevity organ reproduksi berbeda antar varian. MB dan KB didominasi warna merah dan marun, perigonium lebih besar, organ reproduksi lebih panjang, posisi putik sejajar/lebih rendah dari benang sari, dan longevity lebih singkat. MK didominasi kuning hingga oranye, lebih kecil, posisi putik sejajar/lebih tinggi, dan longevity lebih lama. Display pembungaan berbeda antar ras lahan, namun tidak berbeda antar varian. Petir, dengan ukuran populasi terbesar, memproduksi paling banyak pohon berbunga dan total bunga untuk seluruh varian. Ras lahan dan varian berbunga dua kali setahun, namun dengan inisiasi dan durasi yang berbeda. KB berbunga lebih awal di seluruh ras lahan, sedangkan MB paling akhir. MK memiliki durasi pembungaan terpanjang. Perbedaan antar ras lahan lebih dipengaruhi oleh faktor lingkungan seperti ketinggian, jenis tanah, dan iklim. Ras lahan yang lebih rendah, kering, dan panas berbunga lebih awal dan singkat. Peningkatan temperatur dan turunnya status air tanah menyebabkan keguguran massal yang diikuti sequential replacement, mengakibatkan perubahan frekuensi pembungaan. Strategi konservasi cendana di Gunung Sewu perlu dirancang berbasis keragaman genetik, sinkroni pembungaan, dan kompatibilitas antar varian, dengan tetap mempertimbangkan keberagaman tempat tumbuhnya.Kata kunci: cendana; Gunung Sewu; pembungaan; ras lahan; varian bunga The Flowering Characters Variation Among Floral Variants and Landraces Along Geographical Gradients in Gunung SewuAbstractSandalwood was origin to the south-eastern islands of Indonesia, but is recently occured as new land-races in Gunung Sewu, Java island. All of land-races consisted of three floral variants (MK, refers to “merah kecil”; MB, “merah besar”; and KB, “kuning besar”, respectively). This research aimed to determine flowering of these variants among three of land-races which were representing geographical zone in Gunung Sewu: Nglanggeran, Blebera, and Petir. Observation on phenology, sexual organs maturity, floral structure, and display was conducted in 2015. Floral structures varied among variants. MB and KB dominated by red and maroon colors, possessed bigger perigonium, longer sexual organs but with shorter longevity, and similar/lower position of stylus to stamens. MK dominated by yellow to orange colors, smaller, similar/higher position of stylus, and longer longevity. Floral display varied among land-races but were similar among variants. Petir, with biggest population size, produced the most abundant flowers and flowering trees at all variants. Sandalwood flowered twice a year in all of land-races and variants, however, the onset and duration varied. KB flowered earliest while MB was the latest. MK possessed longest flowering period. Flowering varied among land-races due to the altitude, soils, and climatic differences. Lower altitude, drier, and warmer sites flowered earlier and shorter. Mass abortion and sequential replacement, resulting in the alteration on flowering frequency, occured due to the extreme temperature increment. Conservation strategy should be arranged based on genetic differentiation, flowering differences, and crossing abilities among variants. Differences of landscapes, which may contribute to the differences of environmental conditions and flowering processes, should also be considered.