Konsentrasi Klorofil Daun Padi pada Saat Kekurangan Air yang Diinduksi dengan Polietilen Glikol

KONSENTRASI KLOROFIL DAUN PADI PADA SAAT KEKURANGAN AIR YANG DIINDUKSI DENGAN POLIETILEN GLIKOL ABSTRAK Telah dilakukan penelitian mengenai konsentrasi klorofil daun padi (Oryza sativa L.) kultivar Serayu dan IR 64 pada saat kekurangan air yang diinduksi dengan polietilen glikol (PEG). Penelitian ini bertujuan untuk membandingkan konsentrasi klorofil total, klorofil a dan klorofil b pada daun padi pada saat kekurangan air yang diinduksi dengan PEG 8000 dengan mengkultur tanaman padi pada medium dengan potensial air (PA) 0; -0,5 dan -1 MPa. Sampel helaian daun (lamina) untuk tiap perlakuan diambil sebanyak 1 g, dihaluskan dengan mortar dan pestel, lalu diekstraksi dengan alkohol 95% sampai semua klorofil terlarut. Ekstrak disaring dan supernatan ditampung dalam labu ukur 100 ml, lalu ditambahkan alkohol 95% sampai 100 ml. Konsentrasi klorofil diukur dengan spektrofotometer pada panjang gelombang 649 dan 665 nm. Berdasarkan hasil yang diperoleh, tanaman padi kultivar Serayu dan IR 64 mulai mengalami kekeringan pada PEG dengan PA -0,5 MPa dengan ciri-ciri daun yang kering, menggulung dan batang yang berwarna kecoklatan. Perbedaan konsentrasi klorofil total, klorofil a, dan klorofil b pada daun padi kultivar Serayu dan IR 64 diamati pada PEG dengan PA 0; -0,5 dan -0,1 MPa. Kata kunci: konsentrasi klorofil, polietilen glikol (PEG), kekurangan air, padi kultivar Serayu dan IR 64 THE CHLOROPHYLL CONCENTRATION IN RICE LEAVES UNDER POLYETHYLENE-GLYCOL- INDUCED WATER DEFICIT ABSTRACT A research was conducted to evaluate the concentrations of total clorophyll, chlorophyll a and clorophyll b in rice (Oryza sativa L.) leaves under polyethylene-glycol-induced water deficit. The water deficit was induced by culturing the plants in medium containing polyethylene glycol (PEG) 8000 with water potential (PA) 0;-0,5; and -1 MPa for 2 days. Leaf lamina (1 g) was sampled from each treatment at day 0 and 2. Each sample was ground using porcelain mortar and pestle, and extracted with 95% ethanol until all chlorophyll was dissolved. The extract was filtered, the supernatant was collected in 100 ml flask and added with 95% ethanol until 100 ml. The chlorophyll concentration was measured using spechtrophotometer at 649 and 665 nm. The dry and rolled leaves and brown stems were observed in cultivar Serayu and IR 64 that were cultivated in media containing PEG with PA -0,5 and -1,0 MPa. The concentrations of total chlorophyll, chlorophyll a and b in leaves of cultivar Serayu and IR 64 cultivated in media containing PEG with PA 0; -0,5 and -1,0 MPa were different

Comparison of Plant Growth Promoting Rhizobacteria (PGPR) Diversity and Dynamics During Growth of Cilembu Sweet Potato (Ipomoea batatas L var. Rancing) in Cilembu and Jatinangor Site, Indonesia

The growth and quality of Cilembu Sweet Potato is influenced by the colonization of plant growth promoting rhizobacteria (PGPR). In this study, cultivation medium (soil) were sampled on different period of growth time (0 – 4 months) in two different locations, Cilembu (LCI) and Jatinangor (LJA). Isolation were done based on several selective ability of PGPR, followed by sequencing using 16S rRNA. Based on soil properties, LJA contains more clay and slightly more acidic than the LCI, where the C/N ratio at LCI is higher than LJA (13:10). 17 isolates of bacteria and two isolates of Actinomycetes were found in LCI samples, while LJA samples had 17 isolates of bacteria and one isolate of Actinomycetes. The highest abundance of rhizosphere bacteria at LCI and LJA belongs to Firmicutes division, with 58% and 83% of presence, respectively. PGPR diversity increases in LCI site, while it drops after the third month in LJA site. This result indicates that PGPR diversity in LCI site may contribute in taste establishment of Cilembu Sweet Potato