Pengaruh ukuran biji, 5-aminolevulenic acid dan pupuk NPK terhadap perkembangan benih serta pertumbuhan bibit kakao (Theobroma cacao L. var. Lindak)

MU'ADZAH, Dr. diah Rachmawati, M.Si

2008 | Tesis | S2 Biologi

Penelitian pengaruh ukuran biji kakao, 5-Aminolevulenic acid (5-ALA) dan pupuk NPK terhadap perkecambahan benih dan pertumbuhan bibit kakao (Theobroma cacao L.var. Lindak) telah dilakukan di Laboratorium Fisiologi Tumbuhan Fakultas Biologi Universitas Gajah Mada dan rumah kaca Balai Penyuluhan Pertanian Sleman Yogyakarta dari bulan Juli sampai Desember 2007. Penelitian meliputi 2 eksperimen. Eksperimen I bertujuan menguji kemampuan perkecambahan benih dengan 3 ukuran biji (> 2 cm, 1-2 cm, < 1 cm). Untuk masing-masing perlakuan 3 ulangan. Eksperimen II bertujuan untuk mengevaluasi pengaruh kombinasi 5-Aminolevulenic acid (5-ALA) dan pupuk NPK (15:15:15) terhadap pertumbuhan bibit kakao (Theobroma cacao L.var. Lindak) dilakukan dengan rancangan faktorial. Faktor 1 adalah ukuran biji yang terdiri atas 3 aras ( > 2 cm, 1-2 cm, < 1 cm ) sedang faktor 2 adalah kombinasi pupuk NPK (15:15:15) dan 5-Aminolevulenic acid (5-ALA) dengan 4 aras yaitu 0 g NPK + 0 ppm 5-ALA; 1 g NPK + 0,1 ppm 5-ALA; 2 g NPK + 1 ppm 5-ALA, dan 3 g NPK + 10 ppm 5-ALA masing-masing dengan 8 ulangan. Parameter yang diukur adalah kecepatan perkecambahan, tinggi tanaman, diameter batang, jumlah daun, luas daun, kadar klorofil, panjang akar. Selain itu dilakukan pula pengamatan anatomi terhadap morfologi buah dan biji. Data dianalisis dengan ANOVA dan Uji Jarak Duncan 5%. Hasil penelitian menunjukkan bahwa biji kakao ukuran besar (>2 cm) mempunyai kemampuan perkecambahan paling tinggi yaitu 93,33%. Kombinasi perlakuan pupuk NPK (15:15:15) sebanyak 1 g dan 5-Aminolevulenic acid (5-ALA) 0,1 ppm pada umur 14 minggu setelah tanam (MST) dapat meningkatkan tinggi tanaman, diameter batang, jumlah daun kadar klorofil bibit kakao dan luas daun yang signifikan bila dibandingkan dengan kontrol dan perlakuan lainnya. Hasil analisis morfologi terhadap buah kakao (Theobroma cacao L.var. Lindak) menunjukkan bahwa kulit buah ( perikarpium) terdiri atas 3 lapisan yaitu eksokarpium, mesokarpium dan endokarpium. Sedangkan analisis anatomi biji kakao ukuran besar dan ukuran kecil mempunyai struktur yang sama dari luar ke dalam terdiri dari (1) kulit biji dengan 3 lapisan yaitu lapisan luar (epidermis) ; jaringan yang berdinding tebal, licin dan lentur ; lapisan dalam (endodermis) (2) kotiledon, merupakan jaringan penyimpan cadangan makanan. (3) embrio, yang merupakan struktur memanjang dan mempunyai poros embrional.

The research on the influences of cocoa seed size, 5-Aminolevulenic acid (5-ALA) and NPK fertilizer toward seed germination and growth of cocoa seedling (Theobroma cacao L.var. Lindak) has been done in the Laboratory of Plant Physiology at Biology Faculty of Gadjah Mada University and glasshouse of Agriculture extension bureau of Sleman Yogyakarta, started from July to December 2007. The research consists of two experiments. Experiment I was aimed to test the percentage of seed germination of three different seed sizes (.> 2 cm, 1-2 cm, < 1 cm) For each group (size) were performed with 3 replications. Experiment II was to examine the influence of a combination between 5-Aminolevulenic acid (5- ALA) and NPK fertilizer (15:15:15) toward the growth of cocoa (Theobroma cacao L.var. Lindak) seedlings. This experiment was done using factorial design. The first factor is seed size that consists of three groups (>2cm, 1-2 cm and < 1cm). The second factor was the combination of NPK fertilizer (15:15:15) and 5- Aminolevulenic acid (5-ALA) which consists of four levels namely 0g NPK + 0 ppm 5-ALA; 1g NPK + 0,1 ppm 5-ALA; 2 g NPK + 1 ppm 5-ALA and 3g NPK + 10 ppm 5-ALA. Eight replications were performed for each combination treatment. The measured parameters are germination rate, plant height, stem diameter, leaf number, leaf width , chlorophyll content, root length and the morphological structure of fruit and morphological and anatomical structure of seed. The data were analyzed using ANOVA and DMRT at significancy level 5%. Factorial randomized design was used for this research. The results of this research showed that a bigger size cocoa seed (>2 cm) has the greatest germination percentage namely 93,33%. The combination of NPK fertilizer (15:15:15) of 1 g and 5-aminolevulenic acid (5-ALA) of 0,1 ppm applied at the age of 14 weeks after planting increased plant height, stem diameter, leaf number, chlorophyll content of cocoa seedling and the leaf width . These results were significantly different compared to control and other treatments. The morphological analysis research of the cocoa (Theobroma cacao L.var. Lindak) showed that pericarpium consists of three layers namely, exocarpium, mesocarpium and endocarpium. The anatomical analysis of cocoa seed which has big and small size showed smillar from the outside layer to inside consists of (1) seed coat (Spermodermis) consist of three layers namely outside layers (epidermis); the thick, slick and flexible; inside layers (endodermis) (2) cotyledon, which comprises the food storage ; (3) and embrio which has a stretched structure and an embryonic axis.

Kata Kunci : Theobroma cacao L var Lindak,Ukuran giji,Pupuk NPK,Perkecambahan,5,aminolevulenic acid, Lindak cocoa (Theobroma cacao L.var. Lindak), seed size, 5-aminolevulenic acid, NPK fertilizer, germination, growth.