RESPON PERTUMBUHAN DAN MORFOFISIOLOGI TANAMAN KANGKUNG DARAT (Ipomoea reptans Poir) TERHADAP OSMOPRIMING BENIH DAN PUPUK NITROGEN PADA KONDISI KEKERINGAN

ANNISA LATIFA, Dr. Diah Rachmawati, M.Si.

2016 | Tesis | S2 Biologi

Cekaman kekeringan merupakan salah satu faktor penghambat dalam pembudidayaan tanaman kangkung darat (Ipomoea reptans Poir). Solusi dalam mengatasi masalah tersebut adalah melalui teknik osmopriming benih dan pupuk nitrogen. Tujuan dari penelitian ini adalah untuk mengetahui pengaruh osmopriming benih, pupuk nitrogen (urea), serta interaksi keduanya terhadap respon pertumbuhan dan morfofisiologi tanaman kangkung darat (Ipomoea reptans Poir) pada kondisi kekeringan. Tahapan penelitian terdiri atas: 1) percobaan laboratorium yang meliputi uji perkecambahan dan analisis profil protein; 2) percobaan lapangan yang terdiri atas 3 macam perlakuan yaitu osmopriming benih dengan konsentrasi 0%, 5%, 10%, dan 15% (w/v) PEG; pupuk urea dengan dosis 0 mg/kg tanah, 60 mg/kg tanah, dan 120 mg/kg tanah; serta cekaman kekeringan dengan interval penyiraman 1, 3, dan 5 hari sekali. Parameter yang diamati adalah persentase berkecambah, kecepatan berkecambah, keserempakan berkecambah, profil protein, panjang akar, berat kering tajuk, berat kering akar, kadar klorofil, dan kadar prolin. Hasilnya menunjukkan bahwa osmopriming meningkatkan persentase berkecambah, kecepatan berkecambah, keserempakan berkecambah, konsentrasi protein pada benih, panjang akar, berat kering tajuk, berat kering akar, kadar klorofil, dan kadar prolin. Interaksinya dengan cekaman kekeringan meningkatkan panjang akar, berat kering tajuk, berat kering akar, kadar klorofil, dan kadar prolin dengan konsentrasi optimumnya adalah PEG 15%. Pupuk urea meningkatkan panjang akar, berat kering tajuk, berat kering akar, dan kadar klorofil. Interaksinya dengan cekaman kekeringan meningkatkan panjang akar, berat kering tajuk, dan kadar klorofil tetapi menurunkan berat kering akar dan kadar prolin dengan dosis optimum 120 mg/kg tanah pada interval penyiraman 1 dan 3 hari sekali serta 60 mg/kg tanah pada interval penyiraman 5 hari sekali. Interaksi osmopriming-pupuk urea dan interaksi keduanya pada cekaman kekeringan meningkatkan panjang akar, berat kering tajuk, dan kadar klorofil tetapi menurunkan berat kering akar dan kadar prolin. Osmopriming, pupuk urea, dan interaksi keduanya meningkatkan panjang akar, berat kering tajuk, berat kering akar, kadar klorofil, dan kadar prolin tetapi perlakuan pupuk urea cenderung menurunkan berat kering akar dan kadar prolin pada kondisi cekaman kekeringan.

Drought stress is one of inhibiting factors on the cultivation of leafy vegetable (Ipomoea reptans Poir). Hence, solutions to overcome that problems are seed osmopriming and nitrogen fertilizer. The aims of this experiment were to investigate the effect of seed osmopriming, nitrogen fertilizer, and interaction between them to the growth and morphophysiological response of leafy vegetable (Ipomoea reptans Poir) in drought condition. The experiment consisted of: 1) laboratorium experimental including germination test and protein profile analyzes; 2) field experimental consisting of 3 treatments which were seed osmopriming with concentration of 0%, 5%, 10%, and 15% (w/v) PEG; nitrogen fertilizer with concentration of 0 mg/kg soil, 60 mg/kg soil, and 120 mg/kg soil; and drought stress with watering interval of 1, 3, and 5 days. Parameters observed were germination percentage, germination rate, germination syncronization, protein profile, root length, shoots dry weight, roots dry weight, leaves chlorophyl content, and leaves proline content. The results showed that osmopriming increased germination percentage, germination rate, germination syncronization, seed protein concentration, root length, shoots and roots dry weight, leaves chlorophyl content, and leaves proline content. Its interaction with drought stress increased root length, shoots and roots dry weight, leaves chlorophyl content, and leaves proline content by optimum concentration of 15% PEG. Urea increased root length, shoots and roots dry weight, leaves chlorophyl content and its interaction with drought stress increased root length, shoots dry weight, and leaves chlorophyl content but decreased roots dry weight and leaves proline content by optimum dose of 120 mg/kg soil at watering interval of 1 and 3 days, and 60 mg/kg soil at watering interval 5 days. Osmopriming-urea fertilizer interaction and its interaction to drought stress increased root length, shoot dry weight, and chlorophyl content but decreased roots dry weight and leaves proline content. Osmopriming, urea fertilizer, and osmopriming-urea fertilizer interaction increased root length, shoots dry weight, roots dry weight, leaves chlorophyl content, and leaves proline content but urea fertilizer treatment tend to decreased roots dry weight and leaves proline content at drought stress condition.

Kata Kunci : Ipomoea reptans Poir, osmopriming benih, pupuk nitrogen, cekaman kekeringan