Beneficial effects of enhanced UV-B radiation under field conditions: improvement of needle water relations and survival capacity of Pinus pinea L. seedlings during the dry Mediterranean summer

Manetas, Yiannis; Petropoulou, Y.; Stamatakis, Kostas; Nikolopoulos, Dimostenis; Levizou, Efi; Psaras, George K.; Karabourniotis, George

doi:10.1007/978-94-011-5718-6_9

Cited by 54 publications

(61 citation statements)

References 30 publications

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“…The values lower than 0.72 are considered to indicate photo-oxidative damage at PS II (Critchley 1998). Some studies on conifers showed the decrease of potential and actual photochemical efficiency (Naidu et al 1993;Bavcon et al 1996); in others no decrease of photochemical efficiency was observed (Petropoulou et al 1995;Manetas et al 1997;Chalker-Scott and Scott 2004). In our study the effect of UV-B radiation was dependent on the development phase of needles and trees, as well as on environmental conditions (Table 5).…”

Section: High Tolerance To Uv-b Radiationcontrasting

confidence: 39%

“…The higher sensitivity of spruce was also due to low temperatures in the winter period (Bavcon et al 1996). Other investigations revealed the positive effect of UV-B on two Mediterranean Pinus species exposed to drought, which was hypothesised as alleviating UV-B effect (Petropoulou et al 1995;Manetas et al 1997). It is thus difficult to generalize about the UV-B effects on conifer trees.…”

Section: Introductionmentioning

confidence: 94%

“…Plants were exposed to ambient and enhanced (simulating 17% ozone depletion) UV-B levels. We have examined the suggested cumulative effect following longterm exposure (Sullivan and Teramura 1992;Bassman et al 2002), the variation of conifer response to enhanced UV-B correlating with needle development stage (Naidu et al 1993;Latola et al 2001) and the effect of concomitant environmental conditions (Bavcon et al 1996;Petropoulou et al 1995;Manetas et al 1997). This paper offers an insight into complex physiological and growth response of Norway spruce to long-term UV-B exposure under realistic environmental conditions.…”

Section: Introductionmentioning

confidence: 97%

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The effects of enhanced UV-B radiation on physiological activity and growth of Norway spruce planted outdoors over 5 years

Sedej

Gaberščik

2008

Trees

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The responses of Norway spruce [Picea abies (L.) Karst.] to enhanced UV-B radiation during the 5-year treatment performed outdoors have been subjected to ecophysiological and growth analysis. The plants were exposed to UV-B radiation, simulating 17% ozone depletion. Ecophysiological parameters were monitored three times a year on three needle age classes, while growth was analysed at the end of each growth season. Spruce exhibited great variability in the amounts of photosynthetic pigments and methanol-soluble UV-B absorbing compounds, light use efficiency, photosynthesis and respiratory potential. The needle, branch and plant biomass production was not significantly affected during the 5-year treatment. The repeated-measures procedure comparing growth parameters through subsequent seasons, revealed a decrease of branch diameter under enhanced UV-B, which could be interpreted as a cumulative UV-B effect. The effects of UV-B radiation depended on needle development stage, interaction with environmental conditions and stresses. A reduced negative effect of UV-B radiation was observed during the prolonged drought in 2003, which was hypothesised as an alleviating effect. The tolerance of Norway spruce to elevated UV-B was to a large extent due to the high content of methanol-soluble UV-B absorbing compounds that was related neither to environmental conditions, including UV-B dose, nor to the developmental stage of the needles. The current year needles exhibited a tendency to increased production of UV-B absorbing compounds under elevated UV-B radiation. The outdoor study performed under variable environmental conditions showed great complexity of spruce response to enhanced UV-B.

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Section: High Tolerance To Uv-b Radiationcontrasting

confidence: 39%

Section: Introductionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 97%

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The effects of enhanced UV-B radiation on physiological activity and growth of Norway spruce planted outdoors over 5 years

Sedej

Gaberščik

2008

Trees

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“…Thus, the knowledge of the effect of these factors and their interactions on the physiology of seedlings is essential for the management of natural stands. Several studies have examined stone pine seedling's physiological performance under controlled growing conditions, but few have been done in the f ield (Petropoulou et al, 1995;Manetas et al, 1997). Our aim is to study the effect of seedling age on different physiological traits (water status, leaf gas exchange and photoinhibition) of stone pine natural regeneration under a natural light gradient in a 2 years field study, including inter-annual and inter-seasonal variability in the plants' response to environmental conditions.…”

Section: Introductionmentioning

confidence: 99%

Seasonal changes in the physiological activity of regeneration under a natural light gradient in a Pinus pinea regular stand

et al. 2010

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Seasonal courses of chlorophyll a fluorescence, gas exchange parameters and water status, joined to environmental variables, were measured in four age classes of stone pine (Pinus pinea L.) natural regeneration, selected within a natural light gradient in order to cover the whole range of incident light detected within a stone pine regular stand throughout 2007 and 2008. Selection of light conditions was based a priori on the distance of seedlings to the parent trees, expressed by crown radius distances. One-year old seedlings were worse acclimated to the extreme drought conditions recorded in summer (especially in 2008), showing lower predawn and midday Fv/Fm values, slightly lower photosynthetic rates at midday, lower ΦPSII values, lower water potentials (Ψ pd and Ψ min ), and high mortality (90%). The oldest seedlings (class 4, 51-200 cm high), although they do not experience the lowest Ψ min in July 2008, were not able to maintain a positive carbon gain at midday, even showing the lowest photosynthetic rates. However, they rapidly recovered once the climatic conditions were softened in early autumn. During late autumn low Fv/Fm values were found especially in one-year old seedlings, indicating that maximal photochemical efficiency of PSII is sensitive to the autumn temperatures below cero recorded during both years. Thus, stone pine regeneration acclimates its physiology to the seasonal course of temperature and water availability, and this acclimation depended on age class. However, seedling physiology is only slightly affected by differences in light environment, probably related to the low variability recorded in GSF values (0.55 ± 0.01), due to the low density of the stand. We suggest that such low stand densities cannot assure one-year old seedlings' survival, but are sufficient for older seedlings.Key words: stone pine; natural regeneration; drought; cold; gas exchange; photochemical efficiency; water status. ResumenCambios estacionales en la actividad fisiológica del regenerado bajo un gradiente natural de luz en una masa natural de Pinus pinea Durante 2007 y 2008 se midió la evolución estacional de la fluorescencia a la clorofila, de los parámetros de intercambio gaseoso y del estado hídrico, junto con variables ambientales, en el regenerado de cuatro clases de edad de pino piñonero (Pinus pinea L.) en una masa regular de esta especie. Las plantas se eligieron dentro de un gradiente natural de luz, con el objeto de cubrir todo el rango de luz incidente en este tipo de masas. La selección de las condiciones de luz se realizó a priori basándose en la distancia de las plantas a los árboles adultos, expresada en radios de copa. Las plantas de un año se aclimataron peor a las condiciones de sequía extrema del verano (principalmente en 2008), mostrando valores menores de Fv/Fm al mediodía y al amanecer, de tasa fotosintética al mediodía, de ΦPSII, de potenciales hídricos (Ψ pd y Ψ min ) y una mayor mortalidad (90%). Las plantas de mayor edad (clase 4, 51-200 cm de altura), aunque no experimentaron ...

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“…15 Most of the studies pertaining to the effect of UV light on plant growth ranges from wild plant species are limited to African savanna, 16 arctic ecosystems, 17 salt marshes 18,19 and Mediterranean ecosystems. 20 Little or no information exists on the potential impacts of UV-B radiation on exotic species and their invasive behavior. However, there is a possibility that UV induced photochemical effects and associated changes in terms of root secretion chemistry could positively influence to aid in the invasiveness of exotic species.…”

Section: Introductionmentioning

confidence: 99%

Phragmites australisroot secreted phytotoxin undergoes photo-degradation to execute severe phytotoxicity

Rudrappa

Choi

Levia

et al. 2009

Plant Signaling & Behavior

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Our study organism, Phragmites australis (common reed), is a unique invader in that both native and introduced lineages are found coexisting in North America. This allows one to make direct assessments of physiological differences between these different subspecies and examine how this relates to invasiveness. Recent efforts to understand plant invasive behavior show that some invasive plants secrete a phytotoxin to ward-off encroachment by neighboring plants (allelopathy) and thus provide the invaders with a competitive edge in a given habitat. Here we show that a varying climatic factor like ultraviolet (UV) light leads to photo-degradation of secreted phytotoxin (gallic acid) in P. australis rhizosphere inducing higher mortality of susceptible seedlings. The photo-degraded product of gallic acid (hereafter GA), identified as mesoxalic acid (hereafter MOA), triggered a similar cell death cascade in susceptible seedlings as observed previously with GA. Further, we detected the biological concentrations of MOA in the natural stands of exotic and native P. australis. Our studies also show that the UV degradation of GA is facilitated at an alkaline pH, suggesting that the natural habitat of P. australis may facilitate the photo-degradation of GA. The study highlights the persistence of the photo-degraded phytotoxin in the P. australis's rhizosphere and its inhibitory effects against the native plants.

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Beneficial effects of enhanced UV-B radiation under field conditions: improvement of needle water relations and survival capacity of Pinus pinea L. seedlings during the dry Mediterranean summer

Cited by 54 publications

References 30 publications

The effects of enhanced UV-B radiation on physiological activity and growth of Norway spruce planted outdoors over 5 years

The effects of enhanced UV-B radiation on physiological activity and growth of Norway spruce planted outdoors over 5 years

Seasonal changes in the physiological activity of regeneration under a natural light gradient in a Pinus pinea regular stand

Phragmites australisroot secreted phytotoxin undergoes photo-degradation to execute severe phytotoxicity

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