Judul: Vegetative Propagation of Hydrangea anomala subsp. petiolaris in FNK Youngplants BV, The Netherlands
Abstrak: Cultivar production through the vegetative propagation by cuttings is one of important activity in advanced ornamental plant production. The product of this activity in floriculture is well-known as baby plant. Internship activities of baby plant production aim to gain experience and skill both in technical and managerial in abilities in an agricultural enterprise. While the specific aim of the internship is to study the process of baby plant production including the whole activity of the preparation of cuttings, planting, induction of roots and shoot, hardening, sorting, and loading. The study focus in this internship is the effect of different source of cuttings on percentage of living plants; time to induce callus, root, and shoots; induced callus, root, and shoots number; root length and; increment of shoot number. The result showed that both top cuttings and internode cuttings can be used as vegetative propagation of Hydrangea anomala subsp. petiolaris. Average time to induce of callus, root, and shoots were respectively 17, 16.8, and 26.2 days on top cuttings and 11.7, 20.2, and 18 days on internode cuttings. Generally, the company shows a good production process that is represented by 95.9% of proper plant that meet the criteria to be marketed.
Keyword: propagation, baby plant, stem cuttings, root, shoots

Judul: Cultivation, Harvest, and Postharvest of Hortensia Cut Flower (Hydrangea macrophylla) at Kwekerij Figaro B.V., Naaldwijk, South Holland
Abstrak: H. macrophylla merupakan bunga potong yang populer di pasar Eropa karena keindahannya. Vase life menjadi penentu bagi keputusan konsumen dalam membeli bunga potong karena pendeknya vase life dapat menurunkan kepuasan konsumen dan mengurangi nilai estetikanya. Kegiatan magang bertujuan meneliti lebih lanjut proses budidaya H. macrophylla di Kwekerij Figaro B.V. serta mendapatkan informasi mengenai konsentrasi larutan perendam yang tepat untuk mendapatkan vase life H. macrophylla ‘Mammoet’ yang optimum. Proses budidaya yang diamati meliputi kondisi greenhouse, irigasi, pemupukan, pengendalian OPT, produksi, dan pemasaran. Produksi dan penjualan H. macrophylla ‘Mammoet’ mengalami penurunan yang signifikan di periode 2021–2023 dikarenakan masalah pada sistem pengairan yang perlu diperbaiki di periode budidaya berikutnya. Penelitian larutan perendam vase life menggunakan RKLT faktorial dua faktor, yakni larutan Chrysal Grow 20 dan Vaselife Universal Flower Food. Vase life dengan hari paling panjang dan efisien terdapat pada konsentrasi 8 mL L-1 Chrysal Grow 20. Penambahan Vaselife Universal Flower Food 1 mL L-1 pada bunga membuat vase life terpanjang, yakni 9,18 hari, lebih panjang 1,95 hari dibanding perlakuan air (kontrol). Interaksi antar dua larutan menunjukkan hasil yang tidak nyata., H. macrophylla is a popular cut flower in the European market due to its aesthetics. Vase life is a determining factor for consumer decisions when purchasing cut flowers because a short vase life can reduce consumer satisfaction and diminish its aesthetic value. The internship activity aims to further investigate the cultivation process of H. macrophylla at Kwekerij Figaro B.V. and obtain information about the appropriate vase life solution dosage to achieve optimal vase life for H. macrophylla 'Mammoet'. The observed cultivation process includes greenhouse conditions, irrigation, fertilization, pest and disease control, production, and marketing. The production and sales of H. macrophylla 'Mammoet' experienced a significant decline in the period 2021–2023 due to issues with the irrigation system that need to be addressed in the subsequent cultivation periods. The study on vase life solutions used a two-factor RCB design, namely Chrysal Grow 20 and Vaselife Universal Flower Food solutions. The longest and most efficient vase life solution was found at a concentration of 8 mL L-1 Chrysal Grow 20. The addition of 1 mL L-1 Vaselife Universal Flower Food resulted in the longest vase life, which is 9.18 days or 1.95 days longer than the water treatment (control). The interaction between the two solutions showed statistically insignificant results.
Keyword: cultivation, greenhouse, hydrangea, vase life

Judul: Metrik Einstein (Anti-) Self-Dual Berdimensi Empat dengan Metode Cartan
Abstrak: Gravitational field equation can be formulated in differential forms (differential geometry), which describes gravity as a manifestation of the curvature of space-time. Curvature of space-time is characterized by a metric that satisfies the gravitational field equation. With differential forms it can be formulated the (anti-) self-dual Einstein equation, which is a modification of the Cartan structure in (anti-) self-dual basis. Calculation of (anti-) self-dual metric with (anti-) self-dual Einstein equation is simpler than the calculation using Christoffel symbols.
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