Judul: Morphological characterization of Hoya diversifolia Blume growing spontaneously in Bogor Botanical Garden
Abstrak: Hoya diversifolia merupakan tumbuhan epifit yang tumbuh subur pada berbagai inang dengan karakter batang berkulit tebal, kasar, dan retak– retak. Penelitian ini bertujuan untuk mengkarakterisasi tumbuhan H. diversifolia dan menyeleksi tumbuhan H. diversifolia terbaik yang tumbuh spontan di Kebun Raya Bogor untuk dikembangkan sebagai tanaman hias. Karakterisasi dilakukan terhadap karakter kualitatif dan kuantitatif organ vegetatif dan generatif dari 30 individu H. diversifolia. Selanjutnya data ditabulasikan dalam bentuk matrik dan digunakan untuk membangun dendogram dengan index RT (Rogers and Tanimoto) dan metode UPGMA. Hoya diversifolia bervariasi pada warna dan ukuran bunga, daun, dan batang. Berdasarkan karakter kualitatif dan kuantitatif, ditemukan individu H. diversifolia yang berpotensi dikembangkan sebagai tanaman hias. Individu ini memiliki sembilan pedunkel dengan rata- rata 18 pedicel disetiap pedunkel., Hoya diversifolia is an epiphytic plant that thrives on various of host stem with thick-skinned, rough, and cracked character. This study aimed to characterize H. diversifolia plants and selecting the best plants that grow spontaneously in the Bogor Botanical Garden to be developed as an ornamental plant. Morphological characterization of qualitatif and quantitative characters was observed from vegetative and generative organs of 30 individuals of H. diversifolia. Furthermore, the data were tabulated and used to construct a dendogram using index RT (Rogers and Tanimoto) and UPGMA method. H. diversifolia varied in color and size of flowers, leaves, and stems. Based on qualitative and quantitative characters, there was an individual of H. diversifolia potentially to be developed as an ornamental plant. This variant had nice peduncle with 19 pedicel each peduncle. Keywords: Hoya diversifolia Blume, Morphology, Bogor Botanical Garden
Keyword: Hoya diversifolia Blume, morfologi, Kebun Raya Bogor

Judul: Study of Growth and Flowering of Several Indonesian Hoyas (Hoya sp.) Indonesia
Abstrak: Indonesia merupakan negara mega-biodiversity dengan banyak keanekaragaman hayati. Hoya menjadi salah satu kekayaan milik Indonesia dari famili Apocynaceae yang secara alami tumbuh merambat di bawah naungan hutan tropika. Banyaknya spesies hoya belum semuanya diikuti dengan kelengkapan informasi mengenai siklus hidup dan pembungaan, maupun cara budidaya yang optimal. Penelitian ini bertujuan untuk menambah informasi mengenai masa pertumbuhan vegetatif dan generatif hoya, serta morfologi dan anatomi daun hoya. Penelitian dilaksanakan di greenhouse Kebun Percobaan Leuwikopo dan Laboratorium Mikroteknik Program Studi Agronomi dan Hortikultura pada Desember 2022 hingga Juli 2023. Pengumpulan informasi dilakukan melalui tahap pengamatan dan pengukuran dengan parameter vegetatif berupa panjang batang, jumlah batang, jumlah daun, jumlah buku, dan parameter generatif berupa jumlah kuntum bunga, diameter cabang, dan periode pembungaan, serta parameter morfologi dan anatomi daun berupa bentuk daun, bentuk pangkal dan ujung daun serta keberadaan jaringan epidermis, dan jaringan mesofil. Hasil yang didapatkan menunjukkan perbedaan pertumbuhan vegetatif maupun generatif tiap spesies hoya, terutama pada kecepatan tumbuh dan durasi munculnya bunga. Perbedaan juga ditemukan pada bentuk, tipe dan struktur anatomi daun hoya., Indonesia is a mega-biodiversity country with rich biodiversity. Hoya, a member of the Apocynaceae family, is one of tropical epiphytic vines naturally growth under tropical forest. The existing species of hoya not accompanied by complete information regarding the life cycle and flowering yet, as well as optimal cultivation methods. This study aims to add information on the vegetative and generative growth stages of hoya, as well as the morphology and anatomy of its leaves. The research was conducted at the greenhouse of Leuwikopo Experimental Farm and the Microtechnic Laboratory of the Department of Agronomy and Horticulture from December 2022 to July 2023. Data collected by observation and measurement, encompassing vegetative parameters such as branch length, number of branches, number of leaves, and number of nodes, and generative parameters including number of flower buds, branch diameter, and flowering period. Additionally, morphological and anatomical parameters of the leaves, such as leaf shape, base and tip shape, and the existence of epidermal and mesophyll tissues were recorded. The results revealed variations in the vegetative and generative growth among different species of hoya, especially in growth speed and duration of flower appearance. The differences are also found in the shape, type and anatomical structure of hoya leaves.
Keyword: anatomi, generatif, hoya, morfologi, vegetatif

Judul: Hydroxyapatite-Chitosan Composite Coating on Stainless Steel 316 to Improve Corrosion Resistance
Abstrak: Metals that were used in bone implantation should have good corrosion resistance that were not easily corroded when implanted into the body. Metal corrosion resistance of stainless steel 316 can be enhanced through the metal coating by hydroxyapatite-chitosan composite with composition ratio of hydroxyapatite (gram) and chitosan 3% (mL) 0.2:0, 0.2:0.1, 0.2:0.5, 0.2:1.0, and 0.2:1.5. Besides improving the corrosion resistance of metal, the presence of chitosan also maintain the position of hydroxyapatite on metal surfaces. Corrosion resistance increases with increasing amount of chitosan added and the best composition of hydroxyapatite-chitosan composite was 0.2:1.0.
Keyword: