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Estabelecimento e padrões sazonais de produtividade de Kielmeyera coriacea (Spr) Mart. nos cerrados do Planalto Central: efeitos do estresse hídrico e sombreamento

Savannas (cerrados) of Central Brazil are characterized by patches of woody vegetation scattered in a continuous graminoid layer. The more open savanna formations, where the grass layer predominates, are locally known as "campo sujo". Kielmeyera coriacea is a deciduous tree, characteristic...

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Main Authors: Nardoto, Gabriela Bielefeld, Souza, Mônica P., Franco, Augusto C.
Format: Artigo
Language: Portuguese
Published: Sociedade Botânica de São Paulo 2017
Subjects:
Soil water potential
Neotropical savannas
Light availability
Microhabitats
Online Access: http://repositorio.unb.br/handle/10482/25455
https://dx.doi.org/10.1590/S0100-84041998000300011
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spelling ir-10482-254552021-01-08T15:10:00Z Estabelecimento e padrões sazonais de produtividade de Kielmeyera coriacea (Spr) Mart. nos cerrados do Planalto Central: efeitos do estresse hídrico e sombreamento Nardoto, Gabriela Bielefeld Souza, Mônica P. Franco, Augusto C. Soil water potential Neotropical savannas Light availability Microhabitats Savannas (cerrados) of Central Brazil are characterized by patches of woody vegetation scattered in a continuous graminoid layer. The more open savanna formations, where the grass layer predominates, are locally known as "campo sujo". Kielmeyera coriacea is a deciduous tree, characteristic of the "cerrados" of Central Brazil. In this study, we investigated how seasonal changes in soil water availability and light affected productivity patterns and survival of plants of K. coriacea, transplanted in the grass matrix of a "campo sujo" formation. Two-month old plants were transplanted in the first half of the wet season (November-December) of 1994. Most mortality occurred just after plant transplanting, during the wet season. Most of the surviving plants were able to withstand the subsequent dry season, which showed that the dry period was not a major influence on survival. However, in the dry season of the second year, 35% of the surviving plants were removed by armadillos (Dasypus spp). By July of both 1995 and 1996, when soil water potential (<FONT FACE="Symbol">Y</font>soil) reached less than -2.5 MPa at a depth of 5 cm and less than -1.0 MPa at a depth of 15 cm, most of the plants had already lost their leaves. Some of the plants lost all aerial parts and resprouted from the soil in the first months of the wet season, when <FONT FACE="Symbol">Y</font>soil was close to zero. There was little investment in aerial parts during the 28 months of the study period. Plant height increased about 1.5 cm during this period and not more than 3-4 leaves were produced during the wet season of each year. Based on measurements of light availability, estimated CO2 assimilation rates of 5 cm high plants of K. coriacea with horizontal leaves would range between 26 to 40% of the photosynthetic capacity, whereas estimations of CO2 assimilation rates of 50 cm high plants of K. coriacea would reach 80% of the photosynthetic capacity, because plants of this size would not be shaded by the grass layer. In conclusion, these results suggest that the seasonal drought restricted plant productivity of this species. In addition, shading by the grass canopy in the wet season potentially limited plant productivity in the first years of life. Kielmeyera coriacea é uma árvore caducifólia, típica dos cerrados do Planalto Central. Neste estudo, investigou-se como as mudanças no potencial da água do solo (<FONT FACE="Symbol">Y</font>s) e a luz afetaram a produtividade e a sobrevivência de indivíduos jovens de Kielmeyera coriacea transplantados na matriz herbácea de uma vegetação do cerrado, em que os elementos arbustivos e arbóreos são esparsos (campo sujo). Indivíduos de 2 meses de idade foram transplantados na primeira metade da estação chuvosa (novembro-dezembro) de 1994. A maior parte da mortalidade dos indivíduos de Kielmeyera coriacea ocorreu nos primeiros meses após o transplante, durante a estação chuvosa. A grande maioria das plantas sobreviventes conseguiu atravessar sua primeira estação seca, mostrando que o período de estiagem não influenciou na sobrevivência das mesmas. No entanto, durante a época seca do segundo ano, 35% das plantas sobreviventes foram removidas por tatus do gênero Dasypus spp. Em meados de julho de ambos os anos, quando o <FONT FACE="Symbol">Y</font>s alcançou valores inferiores a -2,5 MPa a 5 cm e <FONT FACE="Symbol">Y</font>s < -1,0 MPa a 15 cm de profundidade, a grande maioria das plantas já havia perdido suas folhas. Algumas chegaram a perder toda a parte aérea, que rebrotou do solo nos primeiros meses chuvosos quando o <FONT FACE="Symbol">Y</font>s atinge valores próximos de zero. As plantas não mostraram grande investimento em altura, aumentando 1,5 cm em média, durante o período estudado (28 meses), e não mais de 3-4 folhas por planta foram produzidas durante a estação chuvosa de cada ano. Dados de disponibilidade de luz indicaram que plantas com folhas horizontais localizadas a 5 cm de altura teriam uma assimilação potencial de CO2 entre 26 e 40% da sua capacidade máxima durante a estação chuvosa, enquanto que a 50 cm do solo, onde não há mais sombreamento pelo estrato graminoso, chegaria a 80% do máximo. Assim sendo, nos primeiros anos de vida, a disponibilidade de água restringiria a produtividade desta espécie na seca, enquanto o sombreamento pelo estrato herbáceo limitaria a sua produtividade na época chuvosa. 2017-12-07T04:28:30Z 2017-12-07T04:28:30Z 1998 Artigo Revta. brasil. Bot.,v.21,n.3,p.-,1998 http://repositorio.unb.br/handle/10482/25455 https://dx.doi.org/10.1590/S0100-84041998000300011 pt Acesso Aberto Sociedade Botânica de São Paulo
institution REPOSITORIO UNB
collection REPOSITORIO UNB
language Portuguese
topic Soil water potential
Neotropical savannas
Light availability
Microhabitats
spellingShingle Soil water potential
Neotropical savannas
Light availability
Microhabitats
Nardoto, Gabriela Bielefeld
Souza, Mônica P.
Franco, Augusto C.
Estabelecimento e padrões sazonais de produtividade de Kielmeyera coriacea (Spr) Mart. nos cerrados do Planalto Central: efeitos do estresse hídrico e sombreamento
description Savannas (cerrados) of Central Brazil are characterized by patches of woody vegetation scattered in a continuous graminoid layer. The more open savanna formations, where the grass layer predominates, are locally known as "campo sujo". Kielmeyera coriacea is a deciduous tree, characteristic of the "cerrados" of Central Brazil. In this study, we investigated how seasonal changes in soil water availability and light affected productivity patterns and survival of plants of K. coriacea, transplanted in the grass matrix of a "campo sujo" formation. Two-month old plants were transplanted in the first half of the wet season (November-December) of 1994. Most mortality occurred just after plant transplanting, during the wet season. Most of the surviving plants were able to withstand the subsequent dry season, which showed that the dry period was not a major influence on survival. However, in the dry season of the second year, 35% of the surviving plants were removed by armadillos (Dasypus spp). By July of both 1995 and 1996, when soil water potential (<FONT FACE="Symbol">Y</font>soil) reached less than -2.5 MPa at a depth of 5 cm and less than -1.0 MPa at a depth of 15 cm, most of the plants had already lost their leaves. Some of the plants lost all aerial parts and resprouted from the soil in the first months of the wet season, when <FONT FACE="Symbol">Y</font>soil was close to zero. There was little investment in aerial parts during the 28 months of the study period. Plant height increased about 1.5 cm during this period and not more than 3-4 leaves were produced during the wet season of each year. Based on measurements of light availability, estimated CO2 assimilation rates of 5 cm high plants of K. coriacea with horizontal leaves would range between 26 to 40% of the photosynthetic capacity, whereas estimations of CO2 assimilation rates of 50 cm high plants of K. coriacea would reach 80% of the photosynthetic capacity, because plants of this size would not be shaded by the grass layer. In conclusion, these results suggest that the seasonal drought restricted plant productivity of this species. In addition, shading by the grass canopy in the wet season potentially limited plant productivity in the first years of life.
format Artigo
author Nardoto, Gabriela Bielefeld
Souza, Mônica P.
Franco, Augusto C.
author_sort Nardoto, Gabriela Bielefeld
title Estabelecimento e padrões sazonais de produtividade de Kielmeyera coriacea (Spr) Mart. nos cerrados do Planalto Central: efeitos do estresse hídrico e sombreamento
title_short Estabelecimento e padrões sazonais de produtividade de Kielmeyera coriacea (Spr) Mart. nos cerrados do Planalto Central: efeitos do estresse hídrico e sombreamento
title_full Estabelecimento e padrões sazonais de produtividade de Kielmeyera coriacea (Spr) Mart. nos cerrados do Planalto Central: efeitos do estresse hídrico e sombreamento
title_fullStr Estabelecimento e padrões sazonais de produtividade de Kielmeyera coriacea (Spr) Mart. nos cerrados do Planalto Central: efeitos do estresse hídrico e sombreamento
title_full_unstemmed Estabelecimento e padrões sazonais de produtividade de Kielmeyera coriacea (Spr) Mart. nos cerrados do Planalto Central: efeitos do estresse hídrico e sombreamento
title_sort estabelecimento e padrões sazonais de produtividade de kielmeyera coriacea (spr) mart. nos cerrados do planalto central: efeitos do estresse hídrico e sombreamento
publisher Sociedade Botânica de São Paulo
publishDate 2017
url http://repositorio.unb.br/handle/10482/25455
https://dx.doi.org/10.1590/S0100-84041998000300011
_version_ 1688873817017942016
score 13.657419

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