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Photosynthetic acclimation of Tradescantia albiflora to growth irradiance: Lack of adjustment of light‐harvesting components and its consequences
Author(s) -
Chow W. S.,
Adamson Heather Y.,
Anderson Jan M.
Publication year - 1991
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1111/j.1399-3054.1991.tb02126.x
Subject(s) - acclimatization , photosynthesis , irradiance , photosystem ii , photoinhibition , biology , botany , chlorophyll , tradescantia , horticulture , physics , quantum mechanics
The photosynthetic acclimation of Tradescantia albiflora (Kunth), a trailing ground species naturally occurring in the deep shade of rainforests, was studied in relation to growth irradiance (glasshouse; direct light and 1 to 4 layers of shade cloth, giving 100 to 1.4% relative growth irradiance). Contrary to other irradiance studies of higher plants grown in natural habitats or controlled light environments, the chlorophyll a/b ratios of Tradescantia leaves were low (∼2.2) and constant. Acclimation to growth irradiance caused no changes in the relative amounts of specific Chl‐proteins or the numbers of photosystem I (PSI) and PSII reaction centres on a chlorophyll basis, indicating that the light‐harvesting antenna sizes of PSII and PSI, as well as the photosystem stoichiometry, were independent of growth irradiance. However, the amount of cytochrome f and ATP synthase on a chlorophyll basis increased with increasing the relative growth irradiance from 1.4 to 35%, showing acclimation of electron transport and photophosphorylation capacity. The photosynthetic capacity and ribulose 1, 5‐bisphosphate carboxylase (EC 4.1.1.39) activity also increased with increase of the growth irradiance to 35%. Beyond that, the inflexible PSII/PSI stoichiometry and shade‐type photosystem II/light‐harvesting units in Tradescaniia are a disadvantage for long‐term exposure to high irradiance since the leaves are more prone to photoinhibition.