(2) full flowering (stage 6.3);
(3) beginning of fruit development (stage 7.1); (4) fruit and seed
ripening (stage 8.1). Leaf gas exchanges A, E, gs, Ci and other correlated parameters, such as WUE, were measured bi-weekly using an
open portable system ADC model LCA-4 infrared gas analyser (Analytical Development Co., Hoddesdon, UK). The system was used
in conjunction with a portable temperature and humidity controlled leaf chamber with a surface area of 6.25 cm
2
, on young fully
expanded leaves, between 11:00 a.m. and 1:00 p.m. with environmental light condition. WUE was calculated as the ratio between
net assimilation and transpiration rate (A/E) at leaf level. The leaf
area was measured using an area meter LI-3000A. A sub-sample
of fresh leaves was run through the leaf area meter to calculate
LAI. Chlorophyll content values were recorded on the youngest
fully expanded leaf using Minolta SPAD-502 (Minolta, Japan) to
evaluate the foliar nitrogen status. Two plants were collected at
each sampling date for destructive analyses. In both years, destructive plant measurements were performed by digging plants to a
soil depth of 40 cm, after which the soil of the undisturbed roots
was washed away. The plants were then oven-dried at 65
◦
C until
constant weight was obtained and fruit (ripe and un-ripe) and
total (aboveground and underground biomass) dry weights were
calculated