Judul: Effectivity of Several Holding Solutions on Hydrangea macrophylla L. Vase Life
Abstrak: Hydrangea sebagai bunga potong memiliki umur simpan yang relatif lebih singkat dibandingkan dengan bunga lainnya. Salah satu perlakuan pascapanen yang dapat dilakukan adalah penggunaan larutan penyimpan. Penelitian bertujuan mengetahui larutan penyimpan yang dapat memperpanjang umur simpan bunga hydrangea menggunakan larutan komersial (Chrysal dan Floralife) serta beberapa larutan buatan berupa berbagai kombinasi asam sitrat dan sukrosa. Penelitian menggunakan rancangan acak lengkap (RAL) dengan faktor tunggal berupa larutan penyimpan yang terdiri atas akuades (P0), Chrysal (P1), Floralife (P2) serta kombinasi asam sitrat 300 ppm dan sukrosa 3% (P3). Hasil penelitian menunjukkan bahwa larutan penyimpan buatan dengan kombinasi asam sitrat 300 ppm dan sukrosa 3% dengan pH 3,5 memiliki efektivitas penggunaan larutan yang serupa terhadap larutan penyimpan komersial, khususnya dalam memperpanjang umur simpan dan menjaga warna bunga., Hydrangea as cut flowers has a relatively shorter vase life compared to other flowers. One of the postharvest technologies to extend the vase life of Hydrangea flowers is by using holding solutions. This research was aimed to prolong the vase life of Hydrangea macrophylla using commercially available solutions (Chrysal and Floralife) and several made up solutions containing different concentration of citric acid and sucrose. The experiment was set up in a completely randomised design (CRD) with holding solutions as a single factor, i.e. aquadest (P0), Chrysal (P1), Floralife (P2), and combination between 300 ppm citric acid and 3% sucrose (P3). The result shows that the made-up solution containing 300 ppm citric acid and 3% sucrose with a pH of 3.5 has similar effectivity as commercially available solutions, especially in extending the vase life and maintaining the flower color.
Keyword: asam sitrat, bunga potong, Hydrangea macrophylla, sukrosa, umur simpan

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: Penentuan Nilai Eigen dan Vektor Eigen dari Matriks Tridiagonal 2-Toeplitz dengan Pendekatan Polinomial Chebyshev
Abstrak: The eigenvalues and eigenvectors of a matrix can be determined by finding its characteristic polynomials. The characteristic polynomials of a tridiagonal 2-Toeplitz matrix is shown to be closely connected to polynomials which satisfy the Chebyshev recurrence relationship. If the order of the matrix is odd, then the eigenvalues are found explicitly in terms of the Chebyshev zeros and the eigenvectors are found in terms of the polynomials satisfying the recurrence relationship. For even ordered matrices, the situation is more complicated. The problem in these cases is that although the Chebyshev recurrence formula is still applied, its initial values are not generating Chebyshev polynomials
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