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Decline of Photosynthetic Pigments, Ribulose-1,5-Bisphosphate Carboxylase and Soluble Protein Contents, Nitrate Reductase and Photosynthetic Activities, and Changes in Thylakoid Membrane Protein Pattern in Canopy Shade Grapevine (Vitis Vinifera L. cv. Moscato Giallo) Leaves

2001; Institute of Experimental Botany of the Czech Academy of Sciences; Volume: 39; Issue: 4 Linguagem: Inglês

10.1023/a

1573-9058

Massimo Bertamini, N. Nedunchezhian,

Horticultural and Viticultural Research

In canopy shade leaves of grapevine (Vitis vinifera L. cv. Moscato giallo) grown in the field the contents of chlorophyll (Chl), carotenoids (Car), and soluble protein per fresh mass were lower than in sun leaves. RuBPC activity, in vivo nitrate reductase activity (indicator of nitrate utilisation), apparent electron transport rate, and photochemical fluorescence quenching were also significantly reduced in canopy shade leaves. When various photosynthetic activities were followed in isolated thylakoids, canopy shade leaves exerted a marked inhibition of whole chain and photosystem (PS) 2 activity. Smaller inhibition of PS1 activity was observed even in high-level canopy shade (HS) leaves. The artificial exogenous electron donors, DPC and NH2OH, significantly restored the loss of PS2 activity in HS leaves. Similar results were obtained when Fv/Fm was evaluated by Chl fluorescence measurements. The marked loss of PS2 activity in canopy shade leaves was due to the loss of 47, 43, 33, 28-25, 23, 17, and 10 kDa polypeptides.