Interaksi antara Tanaman Kentang Hitam (Plectranthus rotundifolius (Poir.) Spreng.) dan Cabai (Capsicum annum L.) dalam Percobaan Tumpangsari Ex Vitro

Abstract

Potato and chili are important vegetable commodities in Indonesia. Both are often cultivated in intercropping system. One type of potato is the black potato which is easy to grow on any land. Hybrid red chili varieties TM-999 can be planted in the rainy and dry season. These two plant species were used in this research. This study aimed to revealthe effect of the interaction between black potato and chili plants on their growth in an ex vitro intercropping system, as well as it’s effects on the morphology and histology of the roots. The research method used a completely randomized design (CRD) with two treatments. Both plants were grown on Hoagland liquid medium in 200 mL culture bottles. Control treatment (K) was performed by planting both plant species in monoculture (5 weeks); the first treatment (P1) was the two plant species were planted in monoculture (2 weeks), then the media were exchanged and the growth was observed (3 weeks); and the second treatment (P2) was by planting the two plant species side by side on one medium (5 weeks). The results showed an interaction effect between the two plants, which stimulated the growth of potato plants. However, in chili plants this interaction inhibited their growth. This indicated the presence of allelochemical compounds generated from the interaction between both plants. The allelopathic effect inhibits root growth of potato and chili. Root became thicker and brown, and histology observations demonstrated a color difference between roots in control treatment (K) and in the two other treatments.

Kentang dan cabai merupakan komoditas sayuran penting di Indonesia, keduanya sering dibudidayakan dengan sistem tumpangsari. Salah satu jenis kentang yaitu kentang hitam mudah tumbuh pada lahan apapun. Cabai merah hibrida varietas TM-999 dapat ditanam pada musim hujan dan kemarau. Kedua jenis tanaman ini dipergunakan sebagai bahan penelitian. Penelitian ini bertujuan untuk mengetahui efek interaksi antara tanaman kentang hitam dan cabai terhadap pertumbuhan keduanya dalam sistem tumpangsari secara ex vitro, serta pengaruhnya terhadap morfologi dan histologi akar tanaman tersebut. Metode penelitian menggunakan Rancangan Acak Lengkap (RAL) dengan dua perlakuan dan satu kontrol. Kedua tanaman ditanam pada media cair Hoagland dalam botol kultur berukuran 200 mL. Perlakuan kontrol (K) berupa kentang dan cabai ditanam secara monokultur (5 minggu); perlakuan pertama (P1), kedua jenis tanaman ditanam secara monokultur (2 minggu), kemudian media tanam keduanya saling ditukar, lalu pertumbuhannya diamati (3 minggu); dan perlakuan kedua (P2), kedua jenis tanaman ditanam berdampingan pada satu media (5 minggu). Hasil penelitian menunjukkan adanya efek interaksi antara kentang hitam dan cabai bersifat menstimulus pertumbuhan tanaman kentang. Namun, pada tanaman cabai, efek interaksi ini menghambat pertumbuhannya. Hal ini mengindikasikan adanya senyawa alelokimia yang berasal dari interaksi antartanaman. Efek alelopati juga menghambat pertumbuhan akar. Morfologi akar menjadi lebih tebal dan berwarna cokelat, dan pada pengamatan histologi akar terdapat perbedaan warna antara kontrol (K) dan kedua perlakuan.