Advisor(s)
Abstract(s)
The almond tree is generally recognized as drought-tolerant, though it depends on water resources to achieve
high yields. During the summer months of two consecutive years, several physiological and biochemical parameters
were observed, to understand the almond tree’s seasonal sensitivity and behavior under different irrigation
strategies based on crop evapotranspiration (ETc): T100 optimal water requirement regime (applying
100% ETc); T70 and T35 sustained deficit irrigation regimes (applying 70% and 35% ETc); T100-35 regulated
deficit irrigation regime (reducing the application to 35% ETc during fruit filling stage); and T0 (rainfed). The
total leaf chlorophyll and carotenoid reduction in T0 and T35 treatments was significant compared to T100-35.
Leaf soluble proteins and total soluble sugar contents were significantly higher in non-irrigated trees compared
to other treatments, while the starch content showed the opposite trend. Rainfed trees were under obvious water
stress, displaying the lowest values for relative water content (RWC), stomatal conductance (gs), photosynthetic
rate (A), and transpiration rate (E), and the highest for intrinsic water use efficiency (A/gs). Plant hormones
(ABA and IAA) generally accumulated more in non-irrigated trees. The almond tree has been confirmed as a
drought-tolerant species, and when water is scarce, reducing the water application to 35% ETc during fruit filling
stage, results in no yield losses, and the plant status remains unstressed. However, to get the maximum crop
potential, in years and areas where water is not restricted, full irrigation requirements have been shown to boost
almond tree performance.
Description
Keywords
Gas exchange Photosynthetic pigments Plant hormones Proteins Starch Sugars
Pedagogical Context
Citation
Prgomet, Iva; Pascual-Seva, Núria; Morais, Maria Cristina; Aires, Alfredo; Barreales, David; Castro Ribeiro, António; Silva, Ana Paula; I.R.N.A. Barros, Ana; Gonçalves, Berta (2019). Physiological and biochemical performance of almond trees under deficit irrigation. Scientia Horticulturae. ISSN 0304-4238. p. 1-11