Diameter growth and age of jaboticaba trees (Plinia peruviana (Poir.) Govaerts) native from Southwest of Paraná, Brazil, based on growth-rings

The jaboticaba tree (Plinia peruviana (Poir.) Govaerts) is a native Brazilian species, and its fruits are very popular in Brazil. The purpose of this study was to model the diameter growth, and determine the age of jaboticaba trees in four natural populations in Southwest of Paraná State, Brazil. The knowledge of the growth dynamics of this species is essential to assist management and conservation strategies and to discover when this species was established in the region. Core samples were collected to obtain complete growth series by measurement of annual growth rings. The series were crossdated, seven growth models were adjusted, and the best model for each site and a general model were selected using statistics rules. The time series spanned periods of ~75 to ~100 years, and growth ranged between 0.27 and 0.37 cm year-1. Chapman-Richards' model showed better adherence for locations individually, and Monomolecular when grouped. Because to the age reached by the jaboticaba trees and the high density of this species in these natural populations, consequently named "jaboticabais", it was inferred that there was an anthropogenic action in the dispersion and formation of the settlements through the indigenous and caboclos that inhabited the region before 1940. Also, this is the first work to register and verify the fusion of trunks for species of the Plinia genus using double piths found in samples, a feature that must be considered to avoid overestimating the age of jaboticaba trees based solely on measuring tree diameter.

Morphophysiological changes of Acca sellowiana (Myrtaceae: Myrtoideae) saplings under shade gradient

Understanding morphological and physiological changes under different light conditions in native fruit species in juveniles' stage is important, as it indicate the appropriate environment to achieve vigorous saplings. We aimed to verify growth and morphophysiological changes under shade gradient in feijoa (Acca sellowiana (O. Berg) Burret) to achieve good quality saplings adequate to improve cultivation in orchards. The saplings were grown for twenty-one-month under four shading treatments (0%, 30%, 50%, and 80%). Growth, photosynthetic pigments, gas exchanges, chlorophyll fluorescence, and leaf anatomy parameters were evaluated. Saplings under full sun and 30% shade had higher height and diameter growth and dry mass accumulation due to higher photosynthesis rate. As main acclimatization mechanisms in feijoa saplings under 80% shade were developed larger leaf area, reduced leaf blade thickness, and enhanced quantum yield of photosystem II. Even so, the net CO2 assimilation and the electron transport rate was lower and, consequently, there was a restriction on the growth and dry mass in saplings under deep shade. Therefore, to obtain higher quality feijoa saplings, we recommend that it be carried out in full sun or up to 30% shade, to maximize the sapling vigor in nurseries and, later, this light environment can also be used in orchards for favor growth and fruit production.