Respon Morfologis dan Ekspresi Gen Aquaporin pada Padi IR 64 yang Mengalami Cekaman Kekeringan pada Fase Reproduktif (Morphological Responses and Aquaporin Gene Expression in Rice IR64 under Drought Stress at the Reproductive Stage)

Abstract

Abstrak

Cekaman kekeringan merupakan faktor pembatas penting bagi pertumbuhan dan produktivitas tanaman termasuk padi.      Penelitian ini bertujuan menganalisis respon padi IR64 terhadap cekaman kekeringan dengan pemberian polietilen glikol (PEG) pada fase reproduktif.  Penelitian juga bertujuan menganalisis ekspresi gen aquaporin akibat cekaman kekeringan.  Bibit padi ditanam dalam pot dan perlakuan PEG dengan konsentrasi 108g/L (-0.25MPa) dan 178g/L (-0.52 MPa) diberikan saat munculnya panikula. Perlakuan diberikan selama 2 minggu, kemudian tanaman disiram kembali.  Ekspresi gen diamati pada akhir perlakuan dengan semi kuantitatif real time PCR.  Ekstraksi RNA menggunakan RNeasy plant mini kit, sedangkan sintesis cDNA menggunakan Transcriptor First Strand cDNA Kit.  Hasil penelitian menunjukkan bahwa jumlah malai dan berat total malai berkurang akibat cekaman kekeringan.  Persentase gabah kosong mencapai 84,6% pada perlakuan PEG-0,52 MPa, sedangkan pada perlakuan PEG -0,25 MPa persentase gabah kosong sebesar 67,8%.  Pada kontrol persentase gabah kosong adalah 10,3%.  Ekspresi gen OsPIP2;7 sedikit menurun pada perlakuan PEG -0,52 MPa.

Kata kunci: ekspresi gen, IR64, kekeringan, padi, PEG

Abstract

Drought stress is one of the limiting factors of plant growth and productivity including rice.  The aim of this study was to analyze responses of IR64 rice to polyethylene glycol (PEG)-induced-drought stress at the reproductive stage.  This study also aimed to analyze the expression of aquaporin under drought stress.  Rice seedlings were grown in pot system and PEG treatment at concentration of -0.25MPa (108g/L) and -0.52 MPa (178g/L) were given when the panicles arose.  Treatments were conducted for 2 weeks, after that the plants were rewatered.  Gene expression was evaluated at the end of PEG treatment using semi quantitative real time PCR. RNA was extracted using RNeasy plant mini kit, while cDNA synthesis was done using Transcriptor First Strand cDNA Kit.  The results showed that the number and weight of rice ear were less in plant treated with PEG than in control.  The percentage of empty rice grain reached 84.6% at PEG -0.52 MPa, while at PEG -0.25 MPa the percentage of empty grain was 67.8%.  In control plant, the percentage of empty grain was 10.3%.  Drought stress did not alter the expression of OsPIP2;7. 

Keywords: drought, gene expression, IR64, PEG, rice