Response of Dalbergia miscolobium Benth. seedlings, a cerrado tree species, to mineral nutrient supply

Abstract

-(Response of Dalbergia miscolobium Benth. seedlings, a cerrado tree species, to a mineral nutrient supply). The soil under the Brazilian cerrado vegetation is very poor in nutrients. The aim of this study was to investigate the effect of the addition of a nutrient solution in the early growth of D. miscolobium, a typical cerrado tree species, cultivated in cerrado soil. Seeds were germinated in Petri dishes and seven-day old seedlings were transfered to pots containing cerrado soil. These were supplied once a week with a normal, 1/2 or 1/10 strength nutrient solution. Four growth analysis were done over a period of 145 days from seed imbibition, in terms of dry mass, leaf area and carbohydrate and nitrogen contents. Other derived parameters were also analysed. The addition of a nutrient solution promoted early growth with a preferential separation of dry matter towards the tops; in the control seedlings (no nutrient addition) more dry matter accumulated in the root system. This suggests a preferential investment in root growth in poor soils such as the cerrado ones. Reliable evidence of this is given by the level of carbohydrate and protein which was higher in the roots than in the tops of plants growing in cerrado soil without the addition of nutrients.RESUMO -(Resposta das plântulas de Dalbergia miscolobium Benth., uma espécie arbórea de cerrado, à adição de nutrientes minerais). O solo sob vegetação do cerrado brasileiro é muito pobre em nutrientes. O objetivo deste trabalho foi o estudo do efeito da adição de solução nutritiva sobre o crescimento inicial de D. miscolobium, uma espécie arbórea nativa do cerrado, cultivada em solo de cerrado. As sementes foram germinadas em placas de Petri e plântulas com sete dias foram transferidas para recipientes contendo solo de cerrado. Estas foram supridas, uma vez por semana, com solução nutritiva normal, diluída duas vezes ou diluída 10 vezes. Quatro análises de crescimento foram feitas por um período de 145 dias desde o início da embebição das sementes, em termos de massa de matéria seca, área foliar e conteúdo de carboidratos e de nitrogênio. Outros parâmetros derivados também foram avaliados. A adição da solução nutritiva promoveu o crescimento inicial com partição preferencial de matéria seca para a parte aérea; nas plântulas controle (sem adição de nutrientes) mais matéria seca foi acumulada no sistema radicular. Isto sugere um investimento preferencial no crescimento da raiz em solos mais pobres como os de cerrado.Uma boa evidência sobre isso é dada pelo nível de carboidratos e proteínas, o qual foi maior nas raízes do que nas partes aéreas em plantas crescendo em solo de cerrado sem solução nutritiva.

Growth, photosynthate partitioning and fructan accumulation in plants of Vernonia herbacea (Vell.) Rusby under two nitrogen levels

“…Although rhizophore dry mass was lower in N-limited plants (figure 1), the lower shoot:rhizophore ratio found in these Concerning the growth parameters analyzed, the low values in RGR and NAR indicate that V. herbacea presents a low RGR potential as described for plants native to poor soils (Lambers and Poorter, 1992;Paulilo and Felippe, 1995;Sassaki and Felippe, 1998). Based on their adaptive characteristics to nutrient levels in the soil, Chapin (1980Chapin ( , 1988 classified wild species in two groups: in Type I, growth is always slow even when the plants are cultivated under high nutrient supply, whereas in Type II, a low nutrient offer leads to a marked decrease in growth and to clear symptoms of nutrient deficiency.…”

Germinação de sementes e crescimento de plantas de Diplusodon virgatus Pohl, Lythraceae

“…2), observou-se que fotoperíodos mais longos favoreceram o alongamento dos caules; esse efeito é mais óbvio quando as plantas crescem em terra de mata, provavelmente devido às melhores condições nutricionais desta em relação à terra de cerrado (Arasaki & Felippe 1990;Paulilo & Felippe 1995;Sassaki & Felippe 1998). No entanto, somente no fotoperíodo de 16h foi verificada diferença na altura das plantas em terra de mata e de cerrado.…”

Fructan production in Vernonia herbacea (Vell.) Rusby is related to adequate nitrogen supply and period of cultivation

“…A long term study on growth of V. herbacea under both sufficient and limited nitrogen supply (Cuzzuol et al 2005b) showed that these plants present a low RGR potential, similar to plants native to poor soils (Lambers & Poorter 1992, Paulilo & Felippe 1995, Sassaki & Felippe 1998). According to their response to nutrient levels, the authors characterized V. herbacea as a Type I species, following the classification of Chapin (1980,1988) for wild species.…”

“…It is suggested that the low availability of nutrients in the cerrado soil affects carbon partitioning and leads to specific morphological characteristics such as scleromorphism. Paulilo & Felippe (1995) and Sassaki & Felippe (1998) alleged that the cerrado vegetation accumulates more carbohydrates than proteins due to the low nutrient availability in the soil.…”