Scartazza A*, Proietti S, Moscatello S, Augusti A, Monteverdi M C, Brugnoli E, Battistelli A
Abstract: Two-years-old Juglans regia L. (cv. Lozeronne) seedlings were subjected to drought from August to the end of the growing season. Water potential, photosynthesis, growth and storage carbohydrates accumulation were monitored during the season. Photosynthesis rate was decreased significantly in drought-stressed plants, compared to fully-irrigated controls. Although stomatal conductance was greatly reduced by drought, a clear non-stomatal component of the photosynthetic limitation was evident from Api curves. Stem collar diametral growth was inhibited soon after the onset of the drought period. Soluble carbohydrates and starch contents were determined during the growing season in leaves, bark and wood of roots and stems. At the end of the vegetative season, drought-stressed plants showed a strong reduction in storage carbohydrate content, compared to fully-irrigated controls. Carbon isotope composition of carbohydrates, extracted from different plant organs at the end of the vegetative season, was affected by drought depending on the organ analysed. Late summer drought strongly affected growth characteristics and carbon isotope composition of the new shoots produced in the next spring growth. Particularly, carbon isotope composition of the new shoots, sampled during the early stages of growth, reflected the isotope composition of starch accumulated during the drought period in the previous vegetative season. Growth rate of shoots and stem collar diameter was reduced in plants subjected to drought in the previous year. Growth rate was correlated with the storage carbohydrate contents measured at the onset of the new vegetative season.
Citazione: Scartazza A, Proietti S, Moscatello S, Augusti A, Monteverdi M C, Brugnoli E, Battistelli A (1999). Influenza della siccità estiva sull’accrescimento primaverile in Juglans regia L. . 2° Congresso Nazionale SISEF, Bologna, 20 – 22 Ott 1999, Contributo no. #c2.3.8