scholarly journals The effect of the application of the biological control agent EM1 on gas exchange parameters and productivity of Pisum sativum L. infected with Fusarium oxysporum Schlecht.

2012 ◽  
Vol 63 (2) ◽  
pp. 105-115 ◽  
Author(s):  
Adam Okorski ◽  
Jacek Olszewski ◽  
Katarzyna Głowacka ◽  
Sylwia Okorska ◽  
Agnieszka Pszczółkowska

A pot experiment on different methods of EM 1 application was conducted in the period 2002-2004. The study was carried out under controlled growth conditions. The experimental factor was the method of EM1 application. Before application, the biological preparation EM1 was propagated as recommended by the manufacturer (Greenland). The health status of the aboveground parts of 'Ramrod' pea plants was estimated at the flowering stage. The assessment of pea leaf gas exchange parameters (An, E, Gs, and Ci) was made using a LI-Cor 6400 Portable Photosynthesis System. Soil application of EM1 combined with chemical control contributed to inhibiting Fusarium wilt of pea. Foliar application of EM1 combined with chemical control increased all gas exchange rates of pea leaves. Fusarium wilt of pea insignificantly decreased all gas exchange rates of pea leaves and the number of seeds per pod. The best method of EM1 application was soil treatment combined with chemical control, which increased all yield-related morphometric parameters of pea.

2014 ◽  
Vol 42 (2) ◽  
pp. 386-391 ◽  
Author(s):  
Meral INCESU ◽  
Berken CIMEN ◽  
Turgut YESILOGLU ◽  
Bilge YILMAZ

Salinity continues to be a major factor in reduced crop productivity and profit in many arid and semiarid regions. Seedlings of Diospyros kaki Thunb. and D. virginiana L. are commonly used as rootstock in persimmon cultivation. In this study we have evaluated the effects of different salinity levels on photosynthetic capacity and plant development of D. kaki and D. virginiana. Salinity was provided by adding 50 mM, 75 mM and 100 mM NaCl to nutrient solution. In order to determine the effects of different salinity levels on plant growth, leaf number, plant height, shoot and root dry mass were recorded. Besides leaf Na, Cl, K and Ca concentrations were determined. Also leaf chlorophyll concentration, chlorophyll fluorescence (Fv’/Fm’) and leaf gas exchange parameters including leaf net photosynthetic rate (PN), stomatal conductance (gS), leaf transpiration rate (E), and CO2 substomatal concentration (Ci) were investigated. Significant decrease of leaf number, shoot length and plant dry mass by increasing salinity levels was observed in both rootstocks. D. virginiana was less affected in terms of plant growth under salinity stress. Leaf chlorophyll concentration reduction was higher in the leaves of D. kaki in comparison to D. virginiana in 100 mM NaCl treatment. By increasing salinity levels PN, gS and E markedly decreased in both rootstocks and D. kaki was more affected from salinity in terms of leaf gas exchange parameters. In addition there was no significant difference but slight decreases were recorded in leaf chlorophyll fluorescences of both rootstocks.


Plant Disease ◽  
2007 ◽  
Vol 91 (12) ◽  
pp. 1531-1535 ◽  
Author(s):  
Ibrahim A. M. Saeed ◽  
Ann E. MacGuidwin ◽  
Douglas I. Rouse ◽  
Chris Malek

Field experiments were conducted for three consecutive years to study the effects of low populations of Verticillium dahliae and Pratylenchus penetrans on leaf gas exchange of Russet Burbank potato. Treatments were P. penetrans, V. dahliae, the combination of the nematode with the fungus, and a no-pathogen control. Gas exchange was measured nondestructively on young, fully expanded, asymptomatic leaves one to three times per week starting the ninth week after planting. Infection with either pathogen alone had little or no effect on leaf gas exchange parameters. However, co-infection by both pathogens resulted in reduced leaf light use efficiency (mole of CO2 fixed per mole of photon), lower leaf stomatal conductance, lower leaf water use efficiency (mole of CO2 fixed per mole of water used), and increased intercellular CO2 compared with the no-pathogen control. These effects, additive relative to the impact of each pathogen alone, were first observed 9 weeks after inoculation in the first 2 years of the study and 15 weeks after inoculation in the third year.


2000 ◽  
Vol 80 (4) ◽  
pp. 841-847 ◽  
Author(s):  
Jean-Pierre Privé ◽  
N. Allain

Four primocane-fruiting (PF) red raspberry cultivars, Bogong, Autumn Cascade, Heritage and Dinkum, were grown in exposed or sheltered (50% permeable artificial windbreak) sites fully exposed to prevailing winds in Bouctouche, NB. Shelters were erected at the beginning and removed at the end of each growing season. In the establishment year, all cultivars were evaluated to determine the effects of wind stress on their vegetative and reproductive development and leaf gas exchange. since all cultivars responded similarly to the effect of wind in year one, only Dinkum was monitored in years two and three. In all years, the artificial windbreak resulted in an overall 35% reduction in wind velocity, increased the number of calm days (<5.4 km h−1) and decreased the incidence of strong breezes (>36 km h−1). Interestingly in this maritime climate, the artificial windbreak did not have much of an effect on altering relative humidity, vapour pressure deficits, or air or soil temperature. Plants from sheltered sites consistently had greater above-ground biomass (especially cane dry weight) and longer cane internodes. For two of the three years, leaf area and yield were also greater in the sheltered sites. Leaf gas exchange parameters (Pn, gs and Ci), expressed per unit of leaf area, did not differ between treatments for most of the season, but the sheltered plants retained more leaf area and thus had the potential to fix a greater amount of carbon than the exposed plants. The larger, sheltered plants produced a more extensive fruiting framework, which resulted in increased yields in both the establishment and subsequent year. It is recommended to shelter raspberry plants from wind in the initial establishment years. Key words: Rubus idaeus L., fall-bearing, autumn fruiting, windbreak


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