Summer water stress and shade alter bud size and budburst date in three mediterranean Quercus species

• Published in: Trees (Berlin, West) Vol. 24; no. 1; pp. 89 - 97
• Main Authors: Sanz-Pérez, Virginia, Castro-Díez, Pilar
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Berlin/Heidelberg : Springer-Verlag 01.02.2010; Springer-Verlag; Springer Nature B.V
• Subjects: Agriculture; Biomedical and Life Sciences; Buds; Drought; Environmental conditions; Forestry; Life Sciences; Original Paper; Phenology; Plant Anatomy/Development; Plant growth; Plant Pathology; Plant Physiology; Plant Sciences; Plant structures; Seedlings; Water stress; Carbohydrates; Phenology
• ISSN: 0931-1890; 1432-2285
• DOI: 10.1007/s00468-009-0381-5

Current environmental conditions are known to affect plant growth, morphology, phenology, and therefore, plant performance. However, effects of the previous-year environmental conditions can also affect plant structure by altering bud growth, and proportion and date of budburst. Here, we analysed the effects of previous-year water stress and shade on bud size, percentage, and date of budburst in seedlings of three co-occurring Iberian Quercus species in two independent experiments. Responses of apical, lateral, and basal buds were checked during an annual cycle. In the first experiment, seedlings of two evergreens (Q. coccifera L., Q. ilex subsp. ballota (Desf.) Samp.) and a deciduous-marcescent tree (Q. faginea Lam.) were grown under two levels of summer watering. In the second experiment, seedlings were grown under three light intensities. Soluble sugars and starch in shoots and roots were measured before budburst. Summer drought increased bud size of all species and advanced budburst of Q. ilex and Q. coccifera. Moderate and/or intense shade tended to reduce bud size and delay budburst in all species. These responses seem related to changes in the date of bud formation rather than to the amount of carbon reserves, which were reduced both by drought and shade. Treatments affected percentage of budburst in lateral buds, which was reduced by shade and water stress, probably leading to narrower crowns. These results show that previous-year environmental conditions are relevant for plant phenology and structure. The different responses in budburst date between the deciduous and the evergreens might alter their competition relationships at seedling stage.