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- Effects of CO2 concentration on acclimatization and physiological responses of two cultivars of carob treePublication . Osório, Maria Leonor; Gonçalves, Sandra; Osório, Júlio; Romano, AnabelaThis study reports survival and physiological responses of micropropagated Ceratonia siliqua L. cvs. Galhosa and Mulata plants during ex vitro acclimatization under ambient (AC; 330 μmol mol-1) or elevated (EC; 810 μmol mol-1) CO2 concentration and a photosynthetic photon flux density of 125 μmol m-2 s-1. CO2 enrichment during acclimatization did not improve survival rate that was around 80 % for both treatments. Eight weeks after ex vitro transplantation, photosynthetic capacity and apparent quantum yield in acclimatized leaves were higher in comparison with those in in vitro-grown leaves, without any significant difference between CO2 treatments. Chlorophyll content increased after acclimatization. However, EC led to a decrease in the total amount of chlorophyll in new leaves of both cultivars, compared to those grown at AC. Soluble sugars and starch contents were not markedly affected by growth EC, although starch had significantly increased after transfer to ex vitro conditions. EC induced an increase in the stem elongation and in the effective life of leaves, and a decrease in the number of new leaves.
- Analysis of the volatiles emitted by whole flowers and isolated flower organs of the carob tree using HS-SPME-GC/MSPublication . Custódio, Luísa; Serra, Hugo; Nogueira, José Manuel F.; Gonçalves, Sandra; Romano, AnabelaThe volatiles emitted by fresh whole flowers and isolated flower organs of male, female, and hermaphrodite carob trees (Ceratonia siliqua L.; Leguminosae)were analyzed by headspace solid-phase microextraction followed by capillary gas chromatography and mass spectrometry. The headspace of carob flowers is mainly constituted of high amounts of monoterpenes and sesquiterpenes, and more than 25 compounds were identified. The gender and cultivar affected both the qualitative profile and the relative abundances of the volatiles of whole flowers and isolated floral organs. Linalool and its derivatives (cis-linalool furan oxide, 2,2,6-trimethyl-3-keto-6-vinyltetrahydropyran, cis-linalool pyran oxide, and trans-linalool furan oxide), a-pinene, and a-farnesene were the dominant volatiles. Female flowers had a higher diversity of volatile compounds than males and hermaphrodites, but a lower abundance of the major ones. Similarly, the floral scent of female flowers of cv. Mulata had a higher content of volatiles but a lower abundance of the major ones, when compared to cv. Galhosa. In each of the three gender types of flowers, the nectary disks seemed to be the major source of volatiles.
- Floral analysis and seasonal dynamics of mineral levels in carob tree leavesPublication . Custódio, Luísa; Correia, P. J.; Martins-Loução, M. A.; Romano, AnabelaThe mineral concentration of flowers and the seasonal fluctuation of macro- [nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), and magnesium (Mg)] and micronutrients [iron (Fe), manganese (Mn), zinc (Zn), and copper (Cu)] in leaves of male, female, and hermaphroditic carob trees (Ceratonia siliqua L.) were studied. The nutrient dynamics were linked not only to phenological events, but also to the gender of the trees. The females were able to allocate more nutrients to leaves than male trees, even though male flowers were richer in particular elements such as N and Zn. The hermaphrodites supported the development of both inflorescences and fruits with a lower seasonal variation and a lower leaf nutrient concentration, as compared to the other genders, which may indicate a more efficient use of resources. Flowers had, in general, a higher concentration of N, P, and K, and a lower Mn concentration than in leaves. Flowers of the females had a lower nutrient concentration compared to males or hermaphrodites.
- Cryopreservation of pollen of carob treePublication . Custódio, Luísa; Romano, Anabela; Fernandes, N.; Carneiro, M. F.In this work, anthers isolated from male flowers of carob tree (Ceratonia siliqua L.) at developmental phase II were cryopreserved by vitrification, using a fast freezing method. Different types of carbohydrates at different concentrations, namely sorbitol (0.5 M, 1 M, and 2 M), mannitol (0.5 M and 1 M), sucrose (0.5 M, 1 M, and 2 M), and glucose (0.5 M, I M, and 2 M), namely sorbitol, mannitol, sucrose and glucose, were compared with respect to their capacity of inducing freeze tolerance in pollen of carob tree. Carbohydrates were applied as a pre-treatment to anthers before cryostorage. It was also assessed if the presence of the cryoprotectant during the storage period was beneficial for pollen viability. The viability of cryopreserved pollen was evaluated after 5 and 8 months of storage. The application of the cryoprotectants generally increased pollen viability as compared with the control. The best results were obtained after 5 months storage, in the presence of the cryoprotector, with pollen pre-treated with sucrose 0.5 M. The viability of pollen decreased with increasing the duration of storage period.