Respon Morfofisiologi Sawi Caisim (Brassica juncea L.) Akibat Cekaman Salinitas NaCl

Abstract

Salinity stress is a condition in an environment that has high salt levels which can harm or reduce the growth of plants, including mustard. Plants that are exposed to stress could show different responses both morphologically and physiologically. This study aims to determine the morphophysiological response of caisim mustard (Brassica juncea L.) at several levels of salinity. This study was conducted from June 2019 to October 2019 at the Laboratory of Plant Physiology and Plant Tissue Culture, Faculty of Mathematics and Natural Sciences, University of Sumatera Utara, Medan, North Sumatra. This study used a completely randomized design (CRD) with a control of 0 ppm and four levels salinity concentration of NaCl 2000, 4000, 6000 and 8000 ppm. The result showed that salinity significantly affected the morphophysiological variables of mustard caisim such as plant length, root length, number of leaves, leaf area, root biomass, shoot biomass, root/shoot biomass ratio, chlorophyll A, chlorophyll B and total chlorophyll content. Increasing salinity level did not affect on the stomatal density variable. Increasing NaCl concentration tend to decrease all of mustard variables value, except chlorophyll content. 2000ppm of NaCl concentration increased the content of chlorophyll A up to 106%, chlorophyll B up to 113%, and total chlorophyll up to 109%.

Cekaman salinitas adalah kondisi pada lingkungan yang memiliki kadar garam yang tinggi sehingga dapat merugikan atau menurunkan pertumbuhan tanaman, termasuk sawi. Tanaman yang terkena cekaman dapat memberikan respon yang berbeda-beda baik secara morfologi maupun fisiologi. Penelitian ini bertujuan untuk mengetahui respon morfofisiologi tanaman sawi caisim (Brassica juncea L.) pada beberapa tingkat salinitas. Penelitian dilaksanakan dari bulan Juni 2019 sampai bulan Oktober 2019 di Laboratorium Fisiologi Tumbuhan dan Kultur Jaringan Tumbuhan Fakultas Matematika dan Ilmu Pengetahuan Alam Universitas Sumatera Utara, Medan, Sumatera Utara. Penelitian ini menggunakan Rancangan Acak Lengkap (RAL) dengan perlakuan kontrol yaitu 0 ppm dan empat tingkat konsentrasi salinitas NaCl 2000, 4000, 6000 dan 8000 ppm. Konsentrasi salinitas NaCl berpengaruh nyata pada variabel morfofisiologi sawi caisim yaitu panjang tanaman, panjang akar, jumlah daun, luas daun, biomassa akar, biomassa tajuk, rasio biomassa akar/tajuk, kandungan klorofil A, kandungan klorofil B dan kandungan klorofil total namun tidak berpengaruh nyata pada variabel kerapatan stomata. Konsentrasi NaCl yang meningkat cenderung menurunkan seluruh nilai variabel sawi caisim, kecuali variabel kandungan klorofil. Konsentrasi NaCl 2000 ppm meningkatkan kandungan klorofil A hingga 106%, klorofil B hingga 113% dan klorofil total 109%.