tDaily patterns of leaf and stem water potentials, leaf gas exchanges (net photosynthesis, stomatal con-ductance and transpiration), fruit growth, vascular (phloem and xylem) and transpiration in/outflowswere determined in two subsequent years at regular time intervals during the season on pear trees ofthe cv. Abbé Fétel. Leaf gas exchanges showed higher values in the morning, while fruit shrank due tohigh transpiration water losses which were not balanced by xylem flows. Despite the high rates of tran-spiration, fruit were fully rehydrated in the afternoon thanks to high xylem flows, while phloem importoccurred mostly in the midday hours. During most of the season, fruit growth was sustained above allby the xylem flux which represented upto 85% of fruit total inflows. Later, fruit growth rate decreasedwhile dry matter accumulation increased following a rise in the phloem relative contribution to growth,which reached 50% of fruit total inflows. This is the first report to show how the biophysical mechanismof fruit growth in “Abbé Fétel” pear is based on high water exchanges by xylem and transpiration duringmost of the season. The simultaneous monitoring of leaf gas exchanges and fruit vascular flows duringthe day suggests how until about 95 days after full bloom (DAFB), leaves are stronger “sinks” for water inthe morning while fruit import water mainly during the afternoon, thanks to the increase in leaf waterpotential following stomatal closure.
|Autori:||Morandi, B.;Losciale, P.;Manfrini, L.;Zibordi, M.;Anconelli, S.;Pierpaoli, E.;Corelli Grappadelli, L.|
|Data di pubblicazione:||2014|
|Titolo:||Leaf gas exchanges and water relations affect the daily patterns offruit growth and vascular flows in Abbé Fétel pear (Pyrus communis L.) trees|
|Appare nelle tipologie:||1.1 Articolo in rivista|