Articles
Flashes of UV-C light: a powerful new method for stimulating plant defences against powdery mildew of tomato plants grown in soilless greenhouse conditions
Article number
1378_26
Pages
189 – 194
Language
English
Abstract
Flashes of UV-C light represent an innovative process for stimulating plant defences against a large range of diseases in a large number of crops.
Their effects on severity of disease symptoms by powdery mildew were investigated on Cauralina (very susceptible), Clodano (susceptible) and Brioso (not susceptible) tomato plants grown in soilless greenhouse conditions.
UV-C light was provided by amalgam lamps transported by a trolley at 0.7 km h‑1, delivering 600 J m‑2 in one second at the medium-height level of the crop.
Four treatments were made, every 10 days from May 10 to June 25, 2021. Disease was allowed to develop naturally, and first symptoms were observed around mid-May.
Severity was assessed from pictures taken on leaflets.
Leaf gas exchanges were measured every 10 days.
Chlorophyll fluorescence (ChlF) parameters were derived from induction curves of maximal ChlF taken on leaves.
We observed no negative effect of UV-C flashes on either leaf net assimilation rate (Anet) or photosynthetic capacity.
We even observed positive effects on Anet after treatment two for Cauralina and after treatment one for Clodano. Generally speaking there were no negative effects of UV-C treatments on ChlF parameters.
Disease severity was strongly decreased in Cauralina until June 2 and Clodano until June 21. In Brioso there was still a substantial effect observable on July 19, but then disease severity remained well below 8% in the untreated control all along the trial.
Our observations clearly show that flashes of UV-C light have the potential of decreasing symptoms of powdery mildew on tomato leaves without entailing any negative effect on photosynthesis.
Our results are discussed in the light of other observations made as part of previous trials on other crops.
Avenues are discussed for extending the duration of the stimulating effect of flashes of UV-C light on plant defences.
Their effects on severity of disease symptoms by powdery mildew were investigated on Cauralina (very susceptible), Clodano (susceptible) and Brioso (not susceptible) tomato plants grown in soilless greenhouse conditions.
UV-C light was provided by amalgam lamps transported by a trolley at 0.7 km h‑1, delivering 600 J m‑2 in one second at the medium-height level of the crop.
Four treatments were made, every 10 days from May 10 to June 25, 2021. Disease was allowed to develop naturally, and first symptoms were observed around mid-May.
Severity was assessed from pictures taken on leaflets.
Leaf gas exchanges were measured every 10 days.
Chlorophyll fluorescence (ChlF) parameters were derived from induction curves of maximal ChlF taken on leaves.
We observed no negative effect of UV-C flashes on either leaf net assimilation rate (Anet) or photosynthetic capacity.
We even observed positive effects on Anet after treatment two for Cauralina and after treatment one for Clodano. Generally speaking there were no negative effects of UV-C treatments on ChlF parameters.
Disease severity was strongly decreased in Cauralina until June 2 and Clodano until June 21. In Brioso there was still a substantial effect observable on July 19, but then disease severity remained well below 8% in the untreated control all along the trial.
Our observations clearly show that flashes of UV-C light have the potential of decreasing symptoms of powdery mildew on tomato leaves without entailing any negative effect on photosynthesis.
Our results are discussed in the light of other observations made as part of previous trials on other crops.
Avenues are discussed for extending the duration of the stimulating effect of flashes of UV-C light on plant defences.
Authors
L. Urban, J. Aarrouf, M. Rigaud, L. Rosso, L. Bidel, F. Lauri, R. Tisiot
Keywords
photosynthesis, plant defences, powdery mildew, tomato, UV-C light
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