Changes of leaf water potential and endogenous cytokinins in young apple trees treated with or without paclobutrazol under drought conditions

Leaf growth, predawn leaf water potential (Ψpd), evapotranspiration, stem maximum permeability, and its percentage loss of hydraulic conductivity (PLC) were measured in rooted cuttings of selected clones of Eucalyptus globulus Labill. subjected to well-watered and drought conditions. Drought significantly reduced evapotranspiration, leaf growth and maximum permeability. E. globulus clones lost up to 70% of conductivity at values of Ψpd less negative than –1 MPa. PLC values higher than 85% could not be measured without causing leaf shedding. The coefficient related to the slope of the vulnerability curves ranged from 1.52–2.23. The lowest value was measured in the most drought-resistant clone, as estimated from field trials. Plants from this clone displayed higher drought-induced reductions in maximum permeability than plants from other clones, had significantly smaller leaves and maintained higher values of predawn leaf water potential as soil water content (SWC) declined.

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Transpiration and water potential of young Quercus petraea (M.) Liebl. coppice sprouts and seedlings during favourable and drought conditions

Journal of Forest Science ◽

10.17221/36/2017-jfs ◽

2017 ◽

Vol 63 (No. 7) ◽

pp. 313-323 ◽

Cited By ~ 4

Author(s):

Stojanović Marko ◽

Szatniewska Justyna ◽

Kyselová Ina ◽

Pokorný Radek ◽

Čater Matjaž

Keyword(s):

Forest Management ◽

Water Potential ◽

Leaf Water Potential ◽

Weather Conditions ◽

Growing Season ◽

Adaptive Strategy ◽

Quercus Petraea ◽

Leaf Water ◽

Individual Tree ◽

Drought Conditions

Increased frequency and intensity of drought events consequently affect oak high forests with the process of further decline, compromised growth and questionable natural regeneration. To overcome such difficulties, new adaptive strategies are required. Coppicing, as the oldest way of forest management, might provide some solutions. In our study two contrasting management systems, sessile oak coppice and high forest, were compared at the initial stages of regeneration and forest development. The transpiration of young oak sprouts and seedlings was monitored using sap flow systems during the 2015 growing season. The study of transpiration also included leaf water potential measurements during three measurement campaigns with contrasting weather conditions. Coppice sprouts transpired significantly more than seedlings on the individual tree and stand level during the entire growing season 2015; particularly large differences were observed during drought conditions. Coppice sprouts experienced lower water limitations due to the voluminous and deeper root system as indicated by leaf water potential results. Presented results attribute young coppices as one of the promising adaptable forest management types with a better adaptive strategy at the extreme sites under water limiting conditions.

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