Drought stress in oak seedlings
Approximately 10 % of the acorns produced by the holm oak (Quercus ilex), a dominant Mediterranean forest species, cannot survive drying out. This phenomenon (known as recalcitrance) makes drought tolerance in Q. ilex an interesting field of study, as little is known about recalcitrant seeds. The 'Quercus ilex proteomic studies on the germination and early seedling growth under drought stress' (QUIPROD) project examined how drought affects proteins and other molecules within germinating recalcitrant Q. ilex acorns. Researchers tested various approaches to induce drought stress, and settled on limiting seedlings to one third of their usual water supply. They also collected leaves, root bases and root tips for further study. Physiological studies showed that drought stress caused cell membranes in the roots to weaken, and led to a general decrease in root biomass. In the studies, plants accumulated the amino acid proline as well as large quantities of sugars under stress. QUIPROD then compared the proteome (all the proteins found in a particular part of the plant) of stressed plants to that of normal plants. Changes were observed in proteins involved in metabolism, protein synthesis and breakdown, defence against biotic and abiotic stress, and intracellular transport. The work of QUIPROD has improved knowledge of an important Mediterranean tree species' response to stress. This research will inform plant stress research, plant breeding and forest management in the Mediterranean.
Keywords
Drought stress, oak seedling, acorn, holm oak, Quercus ilex, forest species, recalcitrance, drought tolerance, recalcitrant seed, germination, seedling growth, root biomass, proteome, plant stress, plant breeding, forest management
