PENGGUNAAN SITOKININ UNTUK MENGATASI CEKAMAN KEKERINGAN SELAMA FASE REPRODUKTIF TANAMAN KEDELAI

Abstract

Penelitian dilakukan untuk mengkaji efektifitas penggunaan sitokinin (kinetin) untuk menunda senesen
daun tanaman kedelai yang mengalami kekeringan selama fase reproduktif dan pengaruhnya terhadap hasil
tanaman. Percobaan dilakukan di rumah plastik Fakultas Pertanian, Universitas Jenderal Soedirman, Purwokerto
mulai bulan Januari 2006 sampai April 2006. Rancangan perlakuan adalah faktorial (3x4) yang disusun dalam
Rancangan Acak Lengkap (RAL) dengan tiga ulangan. Faktor pertama berupa kadar air tanah yang
menggambarkan cekaman kekeringan selama fase reproduktif, yaitu kadar air tanah 100% kapasitas lapangan
(KL-100%), kadar air tanah 75% kapasitas lapangan (KL-75%), dan kadar air tanah 50% kapasitas lapangan
(KL-50%). Faktor kedua berupa tingkat konsentrasi zat pengatur tumbuh sitokinin (kinetin), yaitu konsentrasi
0, 20, 40 dan 60 ppm. Pengamatan yang dilakukan meliputi kandungan air nisbi daun, kandungan klorofil daun,
kehijauan daun, kandungan protein daun, laju transpirasi tanaman, jumlah polong, persentase polong isi, jumlah
biji, bobot biji per tanaman dan bobot 100 biji. Hasil penelitian menunjukkan cekaman kekeringan selama fase
reproduktif tanaman kedelai secara umum menurunkan karakter fisiologi dan hasil tanaman kedelai. Kinetin
efektif menunda senesen daun ditinjau dari kandungan klorofil dan protein daun. Penundaan senesen daun pada
tanaman kedelai yang mengalami kekeringan selama fase reproduktif ternyata justru berdampak negatif terhadap
pertumbuhan organ reproduktif.
Kata kunci: kinetin, kekeringan, senesen, kedelai

 

ABSTRACT
The research was designed to study cytokinin application to overcome the drought during reproductive
stages of soybean. It was done in the plastic house Faculty of Agriculture, Jenderal Soedirman University,
located in Purwokerto, Central Java from January 2006 up to April 2006. The experiment was a (3x4) factorial
arranged in Completely Randomized Design (CRD) with three replications. The first factor was soil water
content showing the level of drought, i.e. soil water content 100% field capacity, soil water content 75% field
capacity, and soil water content 50% field capacity. The second factor was the concentration of cytokinin
(kinetin) i.e. 0, 20, 40 and 60 ppm. The observations were done on relative water content of the leaves,
chlorophyll and protein content of the leaves, the level of leaves greenness, transpiration rate, number of pods
and seeds, weight of seeds per plant and weight of 100 seeds. The result showed that the drought during
reproductive stages reduced on all physiological character and seed yield of soybean. Kinetin was effective to
delay leaf senescence that observe on chlorophyll and protein content of leaves. Delaying leaf senescence during
the drought at reproductive stages of soybean exactly influenced negatively on the growth of reproductive
organs.
Key words: kinetin, drought, senescence, soybean