Estudo comparativo do crescimento de plantas de tomate e milho sob condições de salinidade

Neto, Egídio Bezerra; Nogueira, Rejane Jurema Mansur Custódio

doi:10.1590/s1516-89131999000400013

Cited by 2 publications

(1 citation statement)

References 4 publications

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“…Ademais, o número e a massa de frutos foram influenciados positivamente pelo sombreamento de 35%, o que não ocorreu sob luz plena, que manteve produção intermediá-ria, provavelmente devido à fotorrespiração presente em plantas com metabolismo C 3 (Marenco & Lopes, 2005), a exemplo do tomateiro, que pertence à mesma família botânica da maria-pretinha (Bezerra Neto & Nogueira, 1999). Por outro lado, a menor massa e o menor número de frutos no sombreamento de 65% são explicados pela reduzida luminosidade que atingiu o dossel das plantas, a qual pôde ser absorvida e convertida em energia química para crescimento e o desenvolvimento.…”

Section: Resultsunclassified

Análise de crescimento e partição de assimilados em plantas de maria-pretinha submetidas a níveis de sombreamento

Aumonde¹,

Pedó²,

Martinazzo³

et al. 2013

Planta daninha

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RESUMO -A espécie Solanum americanum (maria-pretinha) é considerada planta daninha; por possuir elevada habilidade competitiva e agressividade, ela reduz a produtividade dos cultivos. O trabalho foi conduzido em casa de vegetação e objetivou analisar o crescimento e a partição de assimilados em plantas de maria-pretinha submetidas a três níveis de sombreamento. As plantas foram coletadas em intervalos regulares de sete dias após o transplante até o final do ciclo, sendo determinada a massa seca e a área foliar. A partir dos dados primários, foi aplicada a análise de crescimento, sendo calculados a massa seca total (W t ), as taxas de produção de matéria seca (C t ), crescimento relativo (R w ) e assimilatória líquída (E a ), o índice de área foliar (L), as razões de área foliar (F a ) e massa foliar (F w ), a área foliar específica (S a ), a partição de matéria seca entre órgãos e o número de frutos. Plantas de maria-pretinha cresceram e se desenvolveram melhor sob condição intermediária de luz (65%), em que atingiram maior W t , C t , L, F a, matéria seca de caule, matéria seca de fruto e maior número de frutos, enquanto a luz plena e a redução da luminosidade em nível acentuado, de maneira mais marcante, afetaram negativamente o crescimento e o desenvolvimento, o que possivelmente pode influenciar a habilidade competitiva da maria-pretinha.Palavras-chave: Solanum americanum, área foliar, matéria seca, taxas de crescimento.ABSTRACT -The species Solanum americanum (mary-nightshade) is considered a weed whose highly competitive ability and aggressiveness reduce crop productivity. This work was conducted under greenhouse conditions aiming to analyze the growth and partitioning of assimilates in marynightshade plants subjected to three levels of shading. The plants were collected at regular intervals of seven days after transplantation until the end of the cycle, with dry mass and leaf area being determined. Based on primary data , growth analysis was carried out to calculate total dry matter production (W t ), dry matter production rates (C t ), relative growth (R -w ), net assimilation (E a ), leaf area index (L), relative growth of leaf area and ratios of leaf area (F a ) and leaf mass (F w ), specific leaf area (S a ) and dry matter partitioning between organs. Mary-nightshade plants showed a better growth and development under intermediate light conditions (35% shade), reaching higher W t , C t , L, F a , stem dry matter, fruit dry matter and number of fruit. Full light and reduction of light at a more accentuated level had a negative effect on growth and development, a fact that may influence the competitive ability of these plants.

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Section: Resultsunclassified

Análise de crescimento e partição de assimilados em plantas de maria-pretinha submetidas a níveis de sombreamento

Aumonde¹,

Pedó²,

Martinazzo³

et al. 2013

Planta daninha

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Stomatic behaviour and leaf water potential in young plants ofAnnona squamosasubmitted to saline stress

Jurema

Ibrahim

Albuquerque

2004

Fruits

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Stomatic behaviour and leaf water potential in young plants of Annona squamosa submitted to saline stress. Abstract-Introduction. In saline soils, the water absorption process of the plants is negatively affected, due to the permeability of the roots, leading to hydric stress. Plants under saline stress close their stomas earlier than plants not in these conditions; this causes an increase in stomatal resistance due to the decrease in water potential. The aim of the present research was to detect alterations in the stomatic behaviour and leaf water potential in young plants of Annona squamosa submitted to saline stress. Materials and methods. Sixty-day-old seedlings of A. squamosa were acclimated for 15 days in a greenhouse, before being submitted to different saline treatments. Five treatments (T 0 = 0 mM; T 1 = 25 mM; T 2 = 50 mM; T 3 = 75 mM and T 4 = 100 mM of NaCl in a nutritive solution) were applied with six replications. The evaluations of the stomatic response occurred on the 20th, 30th, 40th, 60th, 80th and 90th days after the beginning of the saline treatments. The transpiration measures, diffusive resistance and leaf temperature were registered in the first mature leaf. The photosynthetically active radiation, relative humidity and air temperature within the greenhouse were simultaneously assessed 60 and 90 days after the beginning of treatments; then the leaf water potential (R leaf) was also measured. Results. During the time of the experiment the leaf temperature and its difference from the air temperature was not affected by NaCl levels, but only 90 days after the beginning of the treatments the values observed in the control plants were lower than those observed in the 25 mM treatment. The diffusive resistance after 40 days was increased in all NaCl treatments. The transpiration, independent of treatment, was reduced by 44.1% (at 60 days) and 13.4% (at 90 days) with the 100-mM treatment compared with the control treatment. The increment in NaCl induced a decrease in R leaf in all treatments, but an equal reduction was observed for each treatment after 60 and 90 days. Conclusion. The NaCl levels affected the transpiration and leaf water potential; however, the leaf water potential showed an equal reduction in all treatments on the 60th and 90th days. Brazil / Annona squamosa / soil salinity / osmotic stress / transpiration / stomata / water potential Résistance stomatique et potentiel hydrique foliaire chez de jeunes plants d'Annona squamosa soumis à des stress salins.

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Estudo comparativo do crescimento de plantas de tomate e milho sob condições de salinidade

Cited by 2 publications

References 4 publications

Análise de crescimento e partição de assimilados em plantas de maria-pretinha submetidas a níveis de sombreamento

Análise de crescimento e partição de assimilados em plantas de maria-pretinha submetidas a níveis de sombreamento

Stomatic behaviour and leaf water potential in young plants ofAnnona squamosasubmitted to saline stress

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