Cold-induced photoinhibition affects establishment of Eucalyptus nitens (Deane and Maiden) Maiden and Eucalyptus globulus Labill

Abstract

The effects of cold-induced photoinhibition on Eucalyptus globulus and Eucalyptus nitens seedlings were assessed between planting and age 23 weeks. The seedlings were subjected to four treatments before planting: non-hardened (NH) E. globulus and E. nitens, coldhardened (CH) E. nitens, and nutrient-starved (NS) E. nitens. Seedlings were planted alongside established 1-year-old E. nitens saplings. The experimental site was at 350 m above sea level, which is considered marginal for the establishment of E. globulus plantations due to low mean minimum temperatures. Cold and sunny conditions after frost increased photoinhibition in the order: NH E. globulus > NH and CH E. nitens > NS and established E. nitens. As a result there was 20% mortality of NH E. globulus seedlings. NS E. nitens seedlings were severely photoinhibited and had high anthocyanin levels at planting; levels of photoinhibition decreased after planting, anthocyanin levels remained high and there was no mortality. Carotenoid levels were low in E. globulus compared to E. nitens treatments. It was concluded that cold-induced photoinhibition is a factor determining the range of environments where E. globulus can be successfully planted, and not frost tolerance alone. Anthocyanin was synthesised in response to increased photoinhibition. Anthocyanin levels were correlated to the severity of the photoinhibition. Thus, E. nitens seedlings nutrient starved in the nursery are pre-conditioned to photoinhibitory conditions experienced soon after planting. This treatment is a useful risk-management tool where cold-induced photoinhibition is likely to occur during seedling establishment.

High solar radiation hinders tree regeneration above the alpine treeline in northern Ecuador

“…We therefore conclude that high radiation is a more important limitation for tree seedling establishment than extreme temperatures per se. Nightly frosts certainly contribute to the adverse conditions for tree regeneration in the pá ramo, but mainly when they are followed by strong sunlight during the day (Ball et al 1991;Close et al 2000;Krause 1994). …”

“…Excess radiation can have negative effects on plants, causing overheating, desiccation, and photoinhibition (Barber and Andersson 1992;Long et al 1994). These negative effects are aggravated by low temperatures (Ball et al 1991;Close et al 2000;Huner et al 1998;Krause 1994), especially frost, which can occur year-round at night at tropical treelines. Cold-induced photoinhibition has been recognized as a limitation for tree seedling establishment at treelines in Australia and North America (Ball et al 1991;Germino and Smith 1999;Germino et al 2002).…”

Effect of low and high temperatures on the photosynthetic performance of Lantana camara L. Leaves in darkness

“…3 2013 temperatures, respectively, since acclimation is a key factor in the regulation of the thermal tolerance. Just after exposure to low temperatures, gradual cold induced photoinhibition was recorded for both populations, reflected in the lower F v /F m as a conse quence of a decrease in F m with similar F 0 [20]. This photoinhibition, higher at below zero temperatures, revealed deactivation of PSII reaction centers [21] preventing overexcitation of photosynthesis and oxi dative damages [22].…”

“…During day time, plants in the field are not only exposed to low or high temperatures but suffer fre quently from synergetic effects of temperatures and high radiation intensities [4,20]. In these field condi tions, excess energy must be dissipated or the chloro plast membranes sustain oxidative damages, which can lead to tissue and/or whole plant death [30], as has been reported in L. camara [11].…”

Nursery fertilisation affects the frost-tolerance and plant quality of Eucalyptus globulus Labill. cuttings

“…These changes allow plants to respond better to transplantation and coping with new environmental conditions. For Eucalyptus spp., the most widely grown commercial hardwood in the world (planted on about 15 Mha of land [2]), various studies have been carried out on the effects of cold conditions on the hardening process [1,9,10,22,24,33,55]. In particular, Euca-* Corresponding author: nonoe@uhu.es lyptus globulus Labill.…”