Terezinha J. R. Câmara

Diferenciação molecular de cultivares elites de bananeira

The objective of this work was to characaterize elite banana genotypes, and those recommended, using RAPD and microsatellites. Forty-seven RAPD primers and 34 microsatellites primers were used. A contamination essay using the AGMI 24-25 primer was also carried out. Tropical variety was considered the standard sample and the Caipira and Prata Grauda, contaminants. Markers were able to separate the cultivars according to their origin and genomic constitution as well as defined molecular profiles for some of the cultivars evaluated. Garantida, Preciosa and Pacovan Ken cultivars presented genetic similarity with both markers. The AGMI 24-25 primer demonstrated high capacity to discriminate the genotypes in the contamination essay.

Water deficit and salt stress diagnosis through LED induced chlorophyll fluorescence analysis in Jatropha curcas L. oil plants for biodiesel

Light-emitting-diode induced chlorophyll fluorescence analysis is employed to investigate the effect of water and salt stress upon the growth process of physicnut(jatropha curcas) grain oil plants for biofuel. Red(Fr) and far-red (FFr) chlorophyll fluorescence emission signals around 685 nm and 735 nm, respectively, were observed and examined as a function of the stress intensity(salt concentration and water deficit) for a period of time of 30 days. The chlorophyll fluorescence(ChlF) ratio Fr/FFr which is a valuable nondestructive and nonintrusive indicator of the chlorophyll content of leaves was exploited to monitor the level of stress experienced by the jatropha plants. The ChlF technique data indicated that salinity plays a minor role in the chlorophyll concentration of leaves tissues for NaCl concentrations in the 25 to 200 mM range, and results agreed quite well with those obtained using conventional destructive spectrophotometric methods. Nevertheless, for higher NaCl concentrations a noticeable decrease in the Chl content was observed. The Chl fluorescence ratio analysis also permitted detection of damage caused by water deficit in the early stages of the plants growing process. A significant variation of the Fr/FFr ratio was observed sample in the first 10 days of the experiment when one compared control and nonwatered samples. The results suggest that the technique may potentially be applied as an early-warning indicator of stress caused by water deficit.

Plant abiotic stress diagnostic by laser induced chlorophyll fluorescence spectral analysis of in vivo leaf tissue of biofuel species

Laser induced fluorescence is exploited to evaluate the effect of abiotic stresses upon the evolution and characteristics of in vivo chlorophyll emission spectra of leaves tissues of brazilian biofuel plants species(Saccharum officinarum and Jatropha curcas). The chlorophyll fluorescence spectra of 20 min predarkened intact leaves were studied employing several excitation wavelengths in the UV-VIS spectral region. Red(Fr) and far-red (FFr) chlorophyll fluorescence emission signals around 685 nm and 735 nm, respectively, were analyzed as a function of the stress intensity and the time of illumination(Kautsky effect). The Chl fluorescence ratio Fr/FFr which is a valuable nondestructive indicator of the chlorophyll content of leaves was investigated during a period of time of 30 days. The dependence of the Chl fluorescence ratio Fr/FFr upon the intensity of the abiotic stress(salinity) was examined. The results indicated that the salinity plays a major hole in the chlorophyll concentration of leaves in both plants spieces, with a significant reduction in the chlorophyll content for NaCl concentrations in the 25 - 200 mM range. The laser induced chlorophyll fluorescence analysis allowed detection of damage caused by salinity in the early stages of the plants growing process, and can be used as an early-warning indicator of salinity stress

Variabilidade genética de genótipos de bananeira (Musa spp) submetidos ao estresse salino

O Brasil e o segundo maior produtor mundial de bananas, sendo Pernambuco o estado que apresenta maior expansao da cultura na regiao do perimetro irrigado do Vale do Sao Francisco em cujas areas, porem, sao frequentes os problemas de salinizacao do solo o que se pode tornar um fator limitante para a cultura. A utilizacao de cultivares tolerantes a salinidade apresenta-se como uma alternativa bastante viavel; assim, identificar genotipos que se adaptem a solos salinos da Regiao Nordeste, e de fundamental importância para os programas de melhoramento. Este trabalho teve por finalidade utilizar marcadores moleculares, obtidos por amplificacao de DNA via Reacao em Cadeia polimerase (PCR) com iniciadores (primers) de RAPD, para determinar a variabilidade genetica entre dez genotipos de banana (Musa spp): Pacovan, Nanicao, Caipira, FHIA18, Calcutta, SN/2, Borneo, M-53, Microcarpa e Lidi, correlacionando-os com a tolerância ao estresse salino. Foram testados 25 primers. O iniciador D0142A07 gerou o maior numero de loci polimorficos, enquanto o D0142B05 originou o menor. Em geral, o polimorfismo gerado com os marcadores de DNA mostrou que, apesar da base genetica estreita, no caso das que sao formadas pelo mesmo grupo genomico, os genotipos de bananeira apresentam variabilidade genetica relativamente alta. As variedades que apresentaram maior tolerância ao estresse salino, como a Pacovan e SN/2, mostraram-se distantes geneticamente, quando comparadas com as mais sensiveis ao sal, como Calcutta e Lidi.

LED induced chlorophyll fluorescence signatures from leaves of Saccharum officinarum seedlings under water deficit stress

LED-induced chlorophyll fluorescence spectral signatures from Saccharum officinarum leaves are employed to evaluate the effect of water deficit upon the plant growing process. The chlorophyll fluorescence spectral analysis is a nondestructive and nonintrusive indicator of the chlorophyll content of leaves and abiotic stress intensity, and is used to monitor the time evolution of the effect of water deficit stress upon plants physiological state. Red and far-red emission signals around 685 nm and 735 nm, respectively, are observed and examined as a function of irrigation amount. The intensity ratio of the fluorescence emissions allow one to detect signs of damage in the early stages of the plants growing process, and before traces of visible stress became apparent. The results indicated an unusual behavior of the fluorescence ratio for water stress that can potentially be used as a discriminator amongst several abiotic stresses.

Variedades de cana-de-açúcar cultivadas in vitro com diferentes fontes de nitrogênio

To verify the behaviour of three sugarcane varieties cultivated in vitro using media with different sources of nitrogen, an experiment was carried out under sterile conditions. Twelve treatments were used, represented by three sugarcane varieties: Co 997 (V1), SP 71-6949 (V2) and SP 70-1143 (V3), and four growth media, differing in the source of N: integral MS salts (M1-control); 4,3 g/L of glutamine as the only source of nitrogen (M2); KNO3 of MS salts as the only source of nitrogen (M3) and KNO3 of MS salts + 3,0 g/l of glutamine (M4). Five replicates were used in a completely randomized design. Based on the variables studied (shoot height and number), significant differences existed among the varieties, except for V1 and V2. There were also differences on growth media, except for M2 and M4. With respect to the shoot number/height ratio, the variety (V2) was superior when grown in media M1 and M3.