Effect of leaf age and nitrogen fertilisation on sporulation of crown rust (Puccinia coronata var. lolii) on perennial ryegrass (Lolium perenne L.)

Plummer, R. M.; Hall, Roger L.; Watt, T. A.

doi:10.1111/j.1744-7348.1992.tb03986.x

Cited by 7 publications

(5 citation statements)

References 16 publications

(12 reference statements)

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“…Leaf age and position have been shown to influence epiphytic population sizes on plants with a variety of morphologies (2,17,25,29,34). Nevertheless, leaf age is rarely considered in sampling procedures for determining microbial population sizes on vegetable crops.…”

mentioning

confidence: 99%

Population Sizes, Immigration, and Growth of Epiphytic Bacteria on Leaves of Different Ages and Positions of Field-Grown Endive (Cichorium endivia var. latifolia)

Jacques

Kinkel

Morris

1995

Appl Environ Microbiol

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Total, fluorescent, and pectolytic epiphytic bacterial population sizes were quantified on leaves of different age groups of broad-leaved endive during field cultivation from leaf emergence until harvest. Greater bacterial population densities (log 10 CFU per square centimeter) were observed on outer leaves than on inner leaves of the plants throughout the growing season. These differences were statistically significant for total bacterial populations at all sampling times and were often significant for fluorescent and pectolytic bacterial populations. At harvest, a linear gradient of decreasing densities of epiphytic bacteria from outer (older) to inner (younger) leaves of the head was significant. Leaf age influenced the frequency distribution and variability of bacterial population sizes associated with leaves of broad-leaved endive. Total bacterial population sizes were greater at leaf emergence for leaves emerging during the second half of the cultivation period than for leaves emerging earlier. The size of fluorescent and pectolytic bacterial populations on newly emerged leaves increased throughout the season as plants aged. To assess the importance of plant age on bacterial immigration at leaf emergence, bacterial densities were quantified on leaves emerging simultaneously on plants of different ages. In two of the three experiments, greater bacterial population sizes were observed on leaves emerging on younger plants. This indicates that factors other than an increase in concentration of airborne bacteria can lead to increases in population sizes at leaf emergence as plants age in the field. Results of leaf pruning experiments suggested that adjacent leaves may act as a barrier for immigration of fluorescent bacteria on newly emerged leaves. Survival of an inoculated strain of Pseudomonas fluorescens on newly emerged leaves generally did not vary with the age of plants. However, these effects were not consistent among experiments, suggesting that interactions among micro-and macroenvironmental conditions, physiological condition of leaves, and accessibility of leaves to airborne bacteria are important in controlling epiphytic bacterial population sizes.

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mentioning

confidence: 99%

Population Sizes, Immigration, and Growth of Epiphytic Bacteria on Leaves of Different Ages and Positions of Field-Grown Endive (Cichorium endivia var. latifolia)

Jacques

Kinkel

Morris

1995

Appl Environ Microbiol

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“…Smaller bacterial population densities on inner leaves in the head of lettuce (Ercolani, 1976), cabbage (Geeson, 1979) and broad-leaved endive (Morris & Lucotte, 1993) at harvest were previously reported. Crops with different morphologies also carry variable population sizes according to leaf position or leaf age during field cultivation (Andrews et al, 1980, Jones et al, 1985Plummer et al, 1992). Our work is the first experimental evidence that leaf age-associated differences at harvest affect the microbiological and market quality of RTU salads during storage.…”

Section: Discussionmentioning

confidence: 79%

“…The influence of leaf age on the likelihood of leaf tissue decay is evident both in terms of quality and quantity of decay. Although for other host-parasite models younger leaves are more susceptible to decay (Jones er al., 1985) or more conducive to fungal sporulation (Plummer et al, 1992) than older leaves, the younger leaves of broad-leaved endive appear less susceptible to marginal necrosis and soft rot than older ones. These differences probably reflect differences in the likelihood of a given bacterial population size (i.e.…”

Section: Discussionmentioning

confidence: 98%

Bacterial population dynamics and decay on leaves of different ages of ready‐to‐use broad‐leaved endive

Jacques¹,

Morris²

1995

Int J of Food Sci Tech

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Mesophilic, fluorescent, and pectolytic bacteria were quantified on leaves of five different age groups (AG) of broad-leaved endive (Cichorium endivia var. latifolia) before and after readyto-use (RTU) processing and daily over their 7-day French 'sell by' period. At harvest. significant differences in bacterial population sizes expressed as log,, colony-forming units (cfu) cm-' were observed among leaves of the different AG resulting in decreasing contamination from outer (-older) to inner (-younger) leaves of the head. This persisted throughout storage at 6°C for RTU-processed leaves separated by age implicating leaf physiology as one of its causes. Leaf age also affected types and frequencies of decay occurring during storage. Although the population sizes of mesophilic, fluorescent and pectolytic bacteria were always positively correlated, the sizes of fluorescent and pectolytic populations could not consistently be predicted from mesophilic ones. Thus fluorescent and pectolytic populations should be quantified independently due to their potential role in decay. Atmospheric changes in the packs resulting from vegetable respiration and microbial activity confirmed the limiting effect of high CO, and low 0, on the development of spoilage without an effect on bacterial populations sizes. The importance of the effect of leaf AG for plant cultivation and industrial production of RTU salads is discussed.

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“…oryzae) of the same crop (Koch and Mew, 1991), crown rust (Puccinia coronata var. lolii) on perennial ryegrass (Lollium perenne L.) (Plummer et al, 1992), blue mould (Peronospora tabacina) of tobacco (Nicotiana tabacum) (Wyatt et al, 1991), bacterial leaf spot (Pseudomonas cichorii) of chrysanthemum (Chrysanthemum morifolium) (Jones et al, 1985); aschochita (Aschochitafabae f. sp. lentis) blight of lentil (Lens culinaris Medik.)…”

Section: Effect On Introduced Populationsmentioning

confidence: 99%

The Effect of Leaf Age and Position on the Dynamics of Microbial Populations on Aerial Plant Surfaces

Jacques¹

Aerial Plant Surface Microbiology

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Effect of leaf age and nitrogen fertilisation on sporulation of crown rust (Puccinia coronata var. lolii) on perennial ryegrass (Lolium perenne L.)

Cited by 7 publications

References 16 publications

Population Sizes, Immigration, and Growth of Epiphytic Bacteria on Leaves of Different Ages and Positions of Field-Grown Endive (Cichorium endivia var. latifolia)

Population Sizes, Immigration, and Growth of Epiphytic Bacteria on Leaves of Different Ages and Positions of Field-Grown Endive (Cichorium endivia var. latifolia)

Bacterial population dynamics and decay on leaves of different ages of ready‐to‐use broad‐leaved endive

The Effect of Leaf Age and Position on the Dynamics of Microbial Populations on Aerial Plant Surfaces

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