44 research outputs found
Comparative studies of compatible and incompatible pepper–Tobamovirus interactions and the evaluation of effects of 24-epibrassinolide
The aim of study was to gain a deeper knowledge about local and systemic changes in photosynthetic processes and sugar
production of pepper infected by
Obuda pepper virus
(ObPV) and
Pepper mild mottle virus
(PMMoV). PSII efficiency,
reflectance, and gas exchange were measured 48 and/or 72
h after inoculation (hpi).
Sugar accumulation was checked
72 hpi and 20 d after inoculation (as a systemic response). Inoculation of leaves with ObPV led to appearance of
hypersensitive necrotic lesions (incompatible interaction), while PMMoV caused no visible symptoms (compatible
interaction). ObPV (but
not PMMoV) lowered F
v
/F
m
(from 0.827 to 0.148 at 72 hpi). Net photosynthesis decreased in
ObPV-infected leaves. In ObPV-inoculated leaves, the accumulation of glucose, fructose, and glucose-6-phosphate was
accompanied with lowered sucrose, malt
oheptose, nystose, and trehalose cont
ents. PMMoV inoculation increased the
contents of glucose, maltose, and raffi
nose in the inoculated
leaves, while glucose-6-phos
phate accummulated in upper
leaves
The effect of light intensity on the production of oat (Avena sativa L.) doubled haploids through oat × maize crosses
Oat haploid embryos were obtained by wide crossing with maize. The effect of light intensity during the growing period of donor plants (450 and 800 µmol m−2 s−1) and in vitro cultures (20, 40, 70 and 110 µmol m−2 s−1) was examined for the induction and development of oat DH lines. Oat florets (26008) from 32 genotypes were pollinated with maize and treated with 2,4-dichlorophenoxyacetic acid. All the tested genotypes formed more haploid embryos when donor plants were grown in a greenhouse (9.4%) compared to a growth chamber (6.1%). The light intensity of 110 µmol m−2 s−1 during in vitro culture resulted in the highest percentage of embryo germination (38.9%), conversion into plants (36.4%) and DH line production (9.2%) when compared with lower light intensities (20, 40 and 70 µmol m−2 s−1). The results show that the growth conditions of the donor plant and light intensity during in vitro culture can affect the development of haploid embryos. This fact may have an impact on oat breeding programs using oat × maize crosses
Chlorophyll a fluorescence parameters in the evaluation of oat DH lines yield components
Chlorophyll a fluorescence can provide insight into the ability of plants to tolerate environmental conditions that can damage photosynthetic apparatus and decrease yield. The aim of the study was to determine the relationship between chlorophyll a fluorescence parameters and yield components of oat DH lines. All DH lines significantly differed in chlorophyll a fluorescence parameters and yield components. The overall performance index of PSII photochemistry (PI), showed the highest variation between DH lines, whereas the lowest had the ratio of variable to maximum fluorescence (Fv/Fm). The highest differences were observed in the number of grains per plant (21.3 to 600). Thousand-grain weight varied from 17.82 g to 41.01 g and the biomass from 8.01 g to 29.31 g. The highest negative correlations were found between Fv/Fm, Area (pool size of electron acceptors from PSII), PI and grain number per plant and biomass. Positive correlations were observed between light energy absorption (ABS/CS), grain number per plant and biomass, as well as the amount of excitation energy trapped in PSII reaction centers (TRo/CS) and biomass. Principal component analysis of chlorophyll a fluorescence parameters, together with yield components, discriminated two oat DH lines groups according to their photosynthetic efficiency and yield