Assessment of phylloplane microorganism populations in Canterbury apple orchards

Abstract

Micro-organism populations on the leaf surface can be an indicator of environmental health in orchards. A method was developed to detect changes in these populations in apple orchards. Firstly, the variation within orchards was investigated by sampling leaves from seven locations within four trees in spring and autumn. The population density and species richness of micro-organisms when grown on PDA showed tree and season effects (P<0.05) but few significant effects of locations within trees or of replicated branches. Based on these findings, the method was modified to study phylloplane micro-organism populations in nine Canterbury orchards at four times during the 1999-2000 season. The method detected an increasing population density and richness (number of recognisable taxonomic units per sample) during the season in all orchards, and higher density and richness (P<0.05) in unconventionally managed orchards compared with conventionally managed orchards.

Impact of phylloplane management on microbial populations

“…An overall higher abundance and diversity of micro-organisms was observed in organic orchards across all sites during spring and autumn, compared with that observed for IFP orchards. A comparable result was also reported for micro-organism populations over spring in Canterbury orchards in a linked study (Bakker et al 2002), which further validates both methodology and some of the observations reported here. Despite lower population richness in IFP orchards, both studies do show some recovery of richness in Canterbury and Hawke's Bay orchards by autumn.…”

“…Following incubation, microbial colony forming units (CFUs) were enumerated and classified into four main groups: bacteria, smooth yeasts, hyphal yeasts and filamentous fungi. The organisms in each group were further classified into Recognisable Taxonomic Units (RTUs) based on different colony growth patterns and phenotypic morphologies (Bakker et al 2002). The population abundance (CFUs/leaf) and the species richness (RTUs/leaf) were determined after 7 days.…”

Yeast isolates to inhibit blue mould and bitter rot of apples

“…Isolates were selected from the eight main morphological yeast RTU as determined in earlier research (Bakker et al 2002;Waipara et al 2002). However, special emphasis was given to isolates of Aureobasidum pullulans (a yeast-like fungus henceforth referred to as a yeast), which is commonly found in New Zealand apple orchards (Pennycook & Newhook 1981;Waipara et al 2002), and is shown to suppress postharvest diseases (Castoria et al 2001;Ippolito et al 2000).…”

Грибы Филлопланы В Городской Среде

“…У грибов, обитающих на поверхности листьев растений, наблюдаются разные пики разнообразия в течение года, что в первую очередь связано с сезонными изменениями климата, а также доступностью органических веществ [11,14,32,40]. Явления смены видового состава грибов филлопланы в течение года (сезонные сукцессии) изучены в разных экологических условиях [17,19,36].…”

“…Они слабо изучены относительно других групп грибов, например патогенных, которые развиваются в тканях листа [1,2,11,32]. По мнению ряда авторов, микромицеты филлопланы не наносят вреда растению [14,27]. Они обитают преимущественно на верхней поверхности листьев, хотя иногда способны развиваться и на нижней стороне листовой пластинки [35].…”