Turkish
Albanian
Arabic
Armenian
Azerbaijani
Belarusian
Bengali
Bosnian
Catalan
Czech
Danish
Deutsch
Dutch
English
Estonian
Finnish
Français
Greek
Haitian Creole
Hebrew
Hindi
Hungarian
Icelandic
Indonesian
Irish
Italian
Japanese
Korean
Latvian
Lithuanian
Macedonian
Mongolian
Norwegian
Persian
Polish
Portuguese
Romanian
Russian
Serbian
Slovak
Slovenian
Spanish
Swahili
Swedish
Turkish
Ukrainian
Vietnamese
Български
中文(简体)
中文(繁體)
Journal of Experimental Botany 2009

The impact of blue light on leaf mesophyll conductance.

Sadece kayıtlı kullanıcılar makaleleri çevirebilir
Giriş yapmak kayıt olmak
Bağlantı panoya kaydedilir
Francesco Loreto
Tsonko Tsonev
Mauro Centritto

Anahtar kelimeler

Öz

Blue light has many direct and indirect effects on photosynthesis. The impact of blue light on mesophyll conductance (g(m)), one of the main diffusive limitation to photosynthesis, was investigated in leaves of Nicotiana tabacum and Platanus orientalis, characterized by high and low g(m), respectively. Leaves were exposed to blue light fractions between 0% and 80% of incident light intensity (300 micromol photons m(-2) s(-1)), the other fraction being supplied as red light. Leaves exposed to blue light showed reduced photosynthesis and unaltered stomatal conductance. The g(m), measured using the chlorophyll fluorescence-based method, was strongly reduced in both plant species. Such a reduction of g(m) may not be real, as several assumptions used for the calculation of g(m) by fluorescence may not hold under blue light. To assess possible artefacts, the electron transport rate measured by fluorescence (J(f)) and by gas-exchange (J(c)) were compared in leaves exposed to different fractions of blue light under non-photorespiratory conditions. The two values were only equal, a prerequisite for correct g(m) measurements, when the illumination was totally provided as red light. Under increasing blue light levels an increasing discrepancy was observed, which suggests that J(f) was not correctly calculated, and that such an error could also upset g(m) measurements. Blue light was not found to change the absorbance of light by leaves, whereas it slightly decreased the distribution of light to PSII. To equate J(f) and J(c) under blue light, a further factor must be added to the J(f) equation, which possibly accounted for the reduced efficiency of energy transfer between the pigments predominantly absorbing blue light (the carotenoids) and the chlorophylls. This correction reduced by about 50% the effect of blue light on g(m). However, the residual reduction of g(m) under blue light was real and significant, although it did not appear to limit the chloroplast CO(2) concentration and, consequently, photosynthesis. Reduction of g(m) might be caused by chloroplast movement to avoid photodamage, in turn affecting the chloroplast surface exposed to intercellular spaces. However, g(m) reduction occurred immediately after exposure to blue light and was complete after less than 3 min, whereas chloroplast relocation was expected to occur more slowly. In addition, fast g(m) reduction was also observed after inhibiting chloroplast movement by cytochalasin. It is therefore concluded that g(m) reduction under blue light is unlikely to be caused by chloroplast movement only, and must be elicited by other, as yet unknown, factors.

Facebook sayfamıza katılın

Bilim tarafından desteklenen en eksiksiz şifalı otlar veritabanı

  • 55 dilde çalışır
  • Bilim destekli bitkisel kürler
  • Görüntüye göre bitki tanıma
  • Etkileşimli GPS haritası - bölgedeki bitkileri etiketleyin (yakında)
  • Aramanızla ilgili bilimsel yayınları okuyun
  • Şifalı bitkileri etkilerine göre arayın
  • İlgi alanlarınızı düzenleyin ve haber araştırmaları, klinik denemeler ve patentlerle güncel kalın

Bir belirti veya hastalık yazın ve yardımcı olabilecek bitkiler hakkında bilgi edinin, bir bitki yazın ve karşı kullanıldığı hastalıkları ve semptomları görün.
* Tüm bilgiler yayınlanmış bilimsel araştırmalara dayanmaktadır

Google Play badgeApp Store badge