This is a repository copy of Tropical tree growth driven by dry-season climate variability.

RESUMO -A Acca sellowiana Berg. (Myrtaceae) é uma frutífera nativa dos planaltos meridionais do Sul do Brasil e que se encontra em processo de domesticação. Seus frutos são doce-acidulados e podem ser consumidos in natura ou empregados para a produção de sucos e doces. Assim, informações sobre o desenvolvimento, morfologia e anatomia de seus frutos são de grande interesse e foram objetos do presente trabalho. O fruto (ovário mais hipanto), no tempo zero (plena floração), tem, em média, 0,6 cm de altura e 0,4 cm de diâmetro, sendo cerca de dez vezes menor que o fruto maduro. Longitudinalmente, identificam-se três regiões distintas: locular, sublocular e prolongamento. Transversalmente, na região mediana, estão delimitadas três regiões: 1) epiderme (casca): com tricomas unicelulares e simples; 2) região parenquimática: rica em braquiesclereídes, isoladas ou em pequenos grupos (2-3 células), com oito feixes vasculares concêntricos perifloemáticos distribuídos radialmente e muitas glândulas esféricas subepidérmicas; 3) região interna (polpa): com células pequenas, cúbicas, nitidamente dispostas em 3-4 camadas ao redor dos lóculos, várias contendo drusa. Quatro lóculos são separados pelos septos e vários óvulos nascem de placentas axiais, com duas fileiras por lóculo. Não ocorrem nectários. À medida que o fruto se desenvolve, surgem, na região intermediária, grupos de células de paredes finas, que crescem muito e diferenciam-se em braquiesclereídes. As placentas crescem, ocupando todo o espaço interior dos lóculos à medida que estes aumentam de tamanho e as sementes se desenvolvem. Assim, o fruto maduro apresenta uma região periférica de consistência firme e gosto adstringente, e uma região central macia e adocicada. Termos para indexação: Goiaba serrana, anatomia do fruto, crescimento do fruto. ANATOMIC STUDY OF Acca sellowiana BERG. FRUIT GROWTHABSTRACT -Acca sellowiana Berg. (Myrtaceae) is a fruit-bearing treelet or shrub native from the highlands of South Brazil. The plant is currently in the domestication process. Its fruit is sweet-acidified and can be consumed raw or be used for the preparation of juice and jam. Thus, information on the development, morphology and anatomy of the fruit is of great interest, and was featured as the objective of this study. The average fruit dimensions (ovary surrounded by the hypanthium) in the bloom stage were 0.6 cm in length and 0.4 cm in diameter, being ten times smaller than the ripe fruit. Longitudinally, three distinct regions were observed: a locular-, a sublocular-and a prolongation region. In a transverse cross-section in the middle of the fruit, three regions were delimited: 1) epidermis (peel) with simple unicellular trichomes. 2) parenchymatous region (flesh) rich in stone cells, isolated or aggregated in small groups of 2-3 cells; with eight radially distributed concentric periphloematic vascular bundles; and with many spherical glands near the epidermis. 3) inner region (pulp) with small cubic cells, organized in 3-4 layers around the locules, various containing d...

The predominance of secondary forest-species in Brazilian subtropical forests highlights the importance of understanding the ecology of these taxa, and dendrochronology provides valuable information about the growth and climate response of tree species. The wide distribution of Alchornea triplinervia (Spreng.) Mull. Arg. (Euphorbiaceae), and the presence of growth rings in its wood, leds to its selection for this study. Samples were collected from 34 trees growing in rainy dense forest fragments in the cities of Blumenau and Brusque, in southern Brazil, and subjected to standard dendrochronological techniques. The local chronology spanned from 1889 to 2013 and the age of the trees ranged from 32 to 125 years. The mean age was 73 years and annual increment was 1.13 mm year À1 ; the diameter and age showed a weak correlation. The results suggest that A. triplinervia growth responded negatively to hot summers and increased rainfall in the previous spring and winter. The high perdiodicity trend characteristic of ENSO activity was reflected in wavelet power spectra of A. triplinervia chronology, affecting positively its growth after strong ENSO events . Negative influences occurred before 1970 during normal ENSO events. Also, there is evidence of the existence of a connection between Pacific and Atlantic sea surface temperatures influencing on tree growth.