Variation of Phyllosphere Microflora of Different Rice Varieties in Sri Lanka and its Relationship to Leaf Anatomical and Physiological Characters

Abstract

Anatomical and physiological characters of the leaf surface and its physico-chemical environment substantially influence the density and diversity of phyllosphere-inhabiting microorganisms, which may include natural antagonists of important pathogens. The objective of this investigation was to quantify the phyllosphere (i.e. leaf surface) microbial population in a range of rice varieties grown in Sri Lanka and to identify the leaf anatomical and physiological characters that determine the density and diversity of phyllosphere microbes. Fifteen rice varieties including both traditional and new high-yielding varieties were used in a planthouse experiment and a field experiment in two consecutive seasons to quantify the phyllosphere microbial population and measure leaf characters that may influence it. There were highly significant intervarietal variations in the density and diversity of epiphytic bacterial, fungal and total microbial populations under both planthouse and field conditions. However, there was no difference between traditional and new, high-yielding varieties in their capacity to harbour epiphytic microbes in the phyllosphere. Total microbial density (TMD) under both conditions showed positive correlations with leaf hair density, stomatal density and transpiration rate. Under planthouse conditions, TMD was also positively correlated with leaf hair length and negatively correlated with leaf temperature. These correlations can be explained in terms of providing favourable microsites on the phylloplane for epiphytic microbial growth.

Soil amendments and cultivar selection can improve rice yield in salt-influenced (tsunami-affected) paddy fields in Sri Lanka

“…The salt-resistant rice variety AT354 (Sumith and de Abeysiriwardena 2004;De Costa et al 2006), which is also recommended for use by the Department of Agriculture of Sri Lanka, showed significantly higher grain yield at the affected site compared to the untreated cultivar AT362, but also compared to the cultivar AT362 grown on soil treated with dolomite and cinnamon ash. 1,000-gain weight was also increased significantly at the affected site and the percentage of unfilled ears was significantly decreased.…”

Heterotrophic and phototrophic 15 N 2 fixation and distribution of fixed 15 N in a flooded rice–soil system

“…Similar results were also observed by short-term 15 N 2 labelling experiments (Eskew et al, 1981;Ito et al, 1980). On the other hand, N 2 -fixing cyanobacteria have been noticed on rice plant phyllospheres and unsubmerged plant shoots under high-humidity conditions (De Costa et al, 2006;Toledo et al, 1995). Therefore, the 15 N stored in rice plants from BNF on plant surfaces or transported from soils need more investigations.…”

Season, Irrigation, Leaf Age, and Escherichia coli Inoculation Influence the Bacterial Diversity in the Lettuce Phyllosphere

“…However, the contributions of these microorganisms to the long-term persistence of the pathogen are currently unclear. Investigations into pathogen-microbiota interactions are difficult because although the phyllosphere microbiota have been identified from multiple plant species, geographical locations, and environmental regimes [5,7,24–26], the relative dominance of different (a) biotic factors on the epiphytic bacterial diversity for any single plant species has yet to be investigated. In this study, our aim was to identify and compare the bacterial diversity in the lettuce phyllosphere at a single geographical site over time during four field trials that included different irrigation methods and inoculation with an attenuated strain of E.…”