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As a result of predicted regional climatic changes the need to select for the more drought-tolerant genotypes (ecotypes) among Mediterranean conifers has become clear. Aleppo pine (Pinus halepensisMill.) seems to be one of the most drought-tolerant pine species. Nevertheless, the existence of geographical trends in their genetic differentiation indicates(More)
Greenhouse-cultured, container-grown seedlings of Aleppo pine (Pinus halepensis Mill.), radiata pine (Pinus radiata D. Don), and interior Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco) were cold acclimated and deacclimated in growth chambers over 24 weeks. Needle and root cold hardiness and root growth potential (RGP) were measured weekly.(More)
We tested the possibility of using tree cores to detect unknown subsurface contamination by chlorinated volatile organic compounds (Cl-VOCs) and petroleum hydrocarbons, a method we term "phytoscreening". The scope and limitations of the method include the following: (i) a number of widespread Cl-VOC contaminants are readily found in tree cores, although(More)
We aimed to elucidate environmental and silvicultural factors that determine the extent of fire-free natural regeneration in east Mediterranean Pinus halepensis forests. The specific aims were to study the potential and identify bottlenecks for natural regeneration and examine the effects of overstory thinning and site preparation treatments. We integrated(More)
Seedlings of Pinus pinea L. growing in plastic containers were treated with seaweed concentrate (SWC). Different concentrations of SWC were applied, 0 to 3 times, to the roots or shoots of the seedlings. Shoot application increased plant weight mainly by increasing shoot growth. This was manifested as increased shoot length and weight and a decrease in the(More)
The effect of stimulating and inhibitory factors on the development of lateral roots was studied in Pinus pinea seedlings grown in a nutrient solution. In an intact root system, only 10–15% of the emerging lateral roots continue to elongate. Removing the tap root tip increased the number and length of the elongating lateral roots but the total number of the(More)
[3H]iso-Pentenyladenine ([3H]iP) was fed for 24 h to the tips of intact and root tip-decapitated Pinus pinea seedlings. Twelve and 24 h after application to the roots of intact plants most of the applied radioactivity (±60%) was transported to the shoot. Root tip removal increased transport of the applied radioactivity to the shoot, but the overall pattern(More)
The tips of the tap roots of Pinus pinea seedlings were dipped in zeatin or iso-pentenyladenine solutions. Immediately after cytokinin application to the root tip or after a 24 h lag phase, [2-14C]IAA was applied to the shoot apex. Treating with zeatin resulted in an increase in [2-14C]IAA transport from the shoot to the root. Iso-pentenyladenine also(More)
The efficient use of trees for taking up volatile organic compounds (VOCs) from the subsurface for remedial and screening purposes is hampered because many poorly quantified co-occurring processes affect VOC concentrations in the tree, the most basic of which are VOC sorption and uptake by roots. Toward understanding the dominant sorption mechanisms, uptake(More)
Tropical forests (and all other forests) have suffered enormous damage in recent decades. If the current rate of forest clearance in the tropics (estimated to be 150 000–250 000 km per year) continues, they will disappear as a major, large-scale ecosystem in many countries during the 21st century. As a result, a chain of environmental problems, including(More)
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