IN INOCULANTS Nodulaid - 17th International Nitrogen Fixation ...
IN INOCULANTS Nodulaid - 17th International Nitrogen Fixation ... IN INOCULANTS Nodulaid - 17th International Nitrogen Fixation ...
17 th International Congress on Nitrogen Fixation Fremantle, Western Australia 27 November – 1 December 2011 Session Details: Wednesday 30 November 2011 Concurrent Session 14 – Cyanobacteria & other organisms 1600 - 1740 Authors: Radziah Othman 13 , Umme Aminun Naher 1 , Zulkifli Hj. Shamsuddin 1 , Halimi Mohd Saud 2 , Mohd Razi Ismail 3 and Khairudin Abdul Rahim 4 1 Department of Land Management, 2 Department of Agriculture Technology, Faculty of Agriculture, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia 3 Institute of Tropical Agriculture, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia 4 Agrotechnology and Biosciences Division, Nuclear Agency Malaysia, Ministry of Science Technology and Innovation (MOSTI), Bangi, 43000 Kajang, Malaysia Presentation Title: Effect of root exuded sugars on biological nitrogen fixation and growth of rice (Oryza sativa) Presentation Time: 1620 – 1640 Biological Nitrogen Fixation (BNF) is an important process in wetland rice ecosystem requiring high energy input. A 15 N tracer study was conducted under glasshouse condition to determine the effect of rice exuded sugars (glucose, galactose and arabinose) on BNF of two locally isolated diazotrophs, Rhizobium sp. Sb16 and Corynebacterium sp. Sb26 in association with two rice genotypes (traditional variety Mayang Segumpal and cultivated variety MR219). Both diazotrophs showed preferences for specific sugars and genotype association. Isolate Sb16 showed high preference for galactose and isolate Sb26 for arabinose. Application of 10 mM sugars either galactose or arabinose in pot experiment (5 kg soil) to the respective rice genotypes enhanced the diazotroph populations, N2 fixation activity and subsequently plant growth. Mayang Segumpal genotype inoculated with Rhizobium Sb16 and applied with galactose increased plant N concentration with 42 ± 1.06 % of the N derived from the atmosphere. MR219 genotype inoculated with Corynebacterium Sb26 and applied with arabinose obtained 40 ± 1.29 % of the N concentration from BNF. Comparing with the uninoculated control, the association between Mayang Segumpal with Sb16 increased plant biomass by 195 ± 40 % and the association between MR219 with Sb26 resulted in biomass increase by 108 ± 37.07 %. In plants fertilized with 60 kg ha -1 of N, inoculated MR219 genotype showed higher biomass increment compared to that of Mayang Segumpal. The association between the plant and diazotrophs with the respective sugars significantly increased plant photosynthetic activity. The study indicated that N2 fixation activity and growth of different rice genotypes can be increased by increasing the availability of specific sugars in the rhizosphere. 88 2011
17 th International Congress on Nitrogen Fixation Fremantle, Western Australia 27 November – 1 December 2011 Session Details: Wednesday 30 November 2011 Concurrent Session 14 – Cyanobacteria & other organisms 1600 - 1740 Authors: Cuddy, W. S. 1 , Forster, B. 2 , Deaker, R. 3 , Summerell, B. A. 4 , Neilan, B. A. 1 ,Gehringer, M. M. 1 1 . School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, 2052, New South Wales. 2. Research School of Biology, Plant Sciences Division, Australian National University, Canberra, 0200, Australian Capital Territory. 3 . Faculty of Agriculture, Food and Natural Resources, University of Sydney, Sydney, 2006, New South Wales. 4. Science and Public Programs, Botanic Gardens Trust, Sydney, 2000, New South Wales. Presentation Title: Cyanobacterial salt physiology and their impact on wheat seedling salt tolerance Presentation Time: 1640 – 1700 Nitrogen-fixing cyanobacteria have been identified in soils and biological soil crusts worldwide. Understanding their potential to support cereal growth, particularly under adverse conditions, is of great interest to crop management and breeding. We assessed the potential benefits of cyanobacteria on growth of wheat seedlings under salt stress. First, three cyanobacterial isolates from wheat fields: a heterocyst-producing Nostoc sp., a Microcoleus vaginatus and a Leptolyngbya sp. were cultured in salinised medium at 5 and 15 dS m -1 and sampled at mid-exponential and stationary growth phases to determine photosynthetic and nitrogen fixation rates using Pulse Amplitude Modulation (PAM) fluorometry and Acetylene Reduction Assays (ARA), respectively. These isolates were then established as soil crusts on sterilized sand into which germinated wheat seeds were planted 1 cm below the surface. Sodium chloride was applied to generate salt stress with electrical conductivities (ECe) of 6 and 13 dS m -1 . Pots were watered to field capacity daily, and the electrical conductivities monitored during seedling development for either 14 days at 6 dS m -1 or 21 days at 13 dS m -1 . Quenching analysis using PAM fluorometry was done on wheat leaves before sampling. Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) was conducted on separated root and shoot material. Both the Nostoc and the nonheterocystous cyanobacteria Microcoleus vaginatus isolates fixed nitrogen at 8 and 6 n moles C2H4 μg Chl a -1 h -1 respectively, without affecting photosynthetic efficiency. The cyanobacterial soil crusts induced significant effects on root and shoot nutrient concentrations, impairing plant salt tolerance. This study provides new evidence for the ability of Microcoleus vaginatus to fix nitrogen, which suggests its contribution to soil ecology may currently be undervalued. We were able to demonstrate that the cyanobacterial isolates used in this study in fact enhanced the salt stress of wheat seedlings, thereby decreasing plant growth. 89 2011
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17 th <strong>International</strong> Congress on <strong>Nitrogen</strong> <strong>Fixation</strong><br />
Fremantle, Western Australia<br />
27 November – 1 December 2011<br />
Session Details: Wednesday 30 November 2011<br />
Concurrent Session 14 – Cyanobacteria & other organisms<br />
1600 - 1740<br />
Authors: Radziah Othman 13 , Umme Aminun Naher 1 , Zulkifli Hj. Shamsuddin 1 , Halimi Mohd Saud 2<br />
, Mohd Razi Ismail 3 and Khairudin Abdul Rahim 4<br />
1 Department of Land Management, 2 Department of Agriculture Technology, Faculty of<br />
Agriculture, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia<br />
3 Institute of Tropical Agriculture, Universiti Putra Malaysia, 43400 UPM Serdang,<br />
Selangor, Malaysia<br />
4 Agrotechnology and Biosciences Division, Nuclear Agency Malaysia, Ministry of<br />
Science Technology and Innovation (MOSTI), Bangi, 43000 Kajang, Malaysia<br />
Presentation Title: Effect of root exuded sugars on biological nitrogen fixation and growth of rice (Oryza<br />
sativa)<br />
Presentation Time: 1620 – 1640<br />
Biological <strong>Nitrogen</strong> <strong>Fixation</strong> (BNF) is an important process in wetland rice ecosystem requiring high energy input.<br />
A 15 N tracer study was conducted under glasshouse condition to determine the effect of rice exuded sugars<br />
(glucose, galactose and arabinose) on BNF of two locally isolated diazotrophs, Rhizobium sp. Sb16 and<br />
Corynebacterium sp. Sb26 in association with two rice genotypes (traditional variety Mayang Segumpal and<br />
cultivated variety MR219). Both diazotrophs showed preferences for specific sugars and genotype association.<br />
Isolate Sb16 showed high preference for galactose and isolate Sb26 for arabinose. Application of 10 mM sugars<br />
either galactose or arabinose in pot experiment (5 kg soil) to the respective rice genotypes enhanced the<br />
diazotroph populations, N2 fixation activity and subsequently plant growth. Mayang Segumpal genotype<br />
inoculated with Rhizobium Sb16 and applied with galactose increased plant N concentration with 42 ± 1.06 % of<br />
the N derived from the atmosphere. MR219 genotype inoculated with Corynebacterium Sb26 and applied with<br />
arabinose obtained 40 ± 1.29 % of the N concentration from BNF. Comparing with the uninoculated control, the<br />
association between Mayang Segumpal with Sb16 increased plant biomass by 195 ± 40 % and the association<br />
between MR219 with Sb26 resulted in biomass increase by 108 ± 37.07 %. In plants fertilized with 60 kg ha -1 of<br />
N, inoculated MR219 genotype showed higher biomass increment compared to that of Mayang Segumpal. The<br />
association between the plant and diazotrophs with the respective sugars significantly increased plant<br />
photosynthetic activity. The study indicated that N2 fixation activity and growth of different rice genotypes can be<br />
increased by increasing the availability of specific sugars in the rhizosphere.<br />
88<br />
2011