Paclobutrazol and water stress induce morphological adaptation in phillyrea angustifolia during hardening
2004
Fernández, J.A. | Balenzategui, L. | Bañón, S. | González, A. | Nicola, S.
Phillyrea angustifolia is a native Spanish species which has recently been considered as suitable for landscaping purposes. We hypothesize that hardening the plants in the nursery could increase their tolerance of drought stress after transplanting. The effects of Paclobutrazol (PBZ) and different irrigation regimes applied to seedlings planted in 4.5-L plastic pots were investigated. PBZ at 0 (untreated control), 30 and 40 ml L-1 per plant was applied. Three drip irrigation treatments were used: T1, plants watered at the water-holding capacity, T2, plants watered 60% of T1, and T3, plants watered 40% of T1. Plants were pot-grown in an unheated greenhouse near the Mediterranean coast of SE Spain. Plant height and stem diameter were measured during growth. Canopy dry weight, leaf area, chlorophyll relative content (CRC), stomata density (SD) and water use efficiency (WUE) were measured at the end of the nursery period. T1 and untreated PBZ plants had the lowest stomata density. PBZ doses significantly reduced canopy weight and leaf area compared to the control. T2 plants had the greatest leaf area and canopy dry weight, while both T2 and T3 treatments had an equally high WUE. CRC did not differ among the treatments. In general, PBZ and irrigation deficit induced morphological adaptations that would allow the plants to overcome transplant shock occurring later in the landscape.
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