scholarly journals Gas exchange parameters in leaves and ears of winter wheat Tricitum aestivum L. and its productivity under fungicide control conditions

2012 ◽  
Vol 63 (2) ◽  
pp. 135-147
Author(s):  
Joanna K. Jarmołkowicz ◽  
Jacek Olszewski

A research experiment was conducted in which rates of photosynthesis and transpiration were measured in leaves and ears of two winter wheat varieties grown under fungicide control conditions and without fungicide control. A LI-COR 6400 portable gas exchange system was used in the investigations. In most cases the fungicide Juwel was shown to have no effect on the gas exchange processes, whereas the other of the fungicidal agents applied - Swing - significantly decreased the gas exchange rates measured. Measurements of gas exchange parameters in ears showed that the intensity of gas exchange was low, in particular at the later stage of ear development. But the applied fungicide caused higher release of CO<sub>2</sub> into the atmosphere than its uptake. Furthermore, the applied fungicides were found to significantly increase grain yield compared to the control treatment, both in the first and second year of the study. Among the tested varieties, 'Nutka' was characterized by higher productivity, in spite of lower 1000 kernel weight. However, this cultivar developed longer ears with a larger amount of grains.


2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Qiu Xinqiang ◽  
Zhang Yushun ◽  
Qin Haixia ◽  
Wang Min ◽  
Wang Yanping ◽  
...  

Drought significantly threatens crop productivity and food security worldwide. However, the severity of drought is predicted to increasingly intensify in the future. To provide an antidrought strategy for farmers and breeders, the response of stomatal behavior of crops to water stress should be well studied. In this study, a lysimeter experiment was conducted to study the relationship between gas exchange parameters and grain yields of winter wheat. Light, moderate, and severe drought levels were imposed at seedling, jointing, heading, and filling stages. The results showed that crop evapotranspiration (ETc, mm) of winter wheat during the entire growing season was limited by drought imposed at any growth stage, and ETc under severe drought treatment was always the lowest. The stomatal limitation value had a significant linear correlation with the stomatal conductance (Gs, μmol mol H2O m–2 s–1) and transpiration rate (Tr, mmol H2O m–2 s–1). Light and moderate drought levels at the seedling stage did not generate irreversible physiological stress on wheat plants, while severe drought at any growth stage caused significant reduction in gas exchange parameters and grain yields. Theoretical threshold values of leaf water use efficiency (WUEl) for light, moderate, and severe drought levels were 2.62, 3.36, and 4.11 μmol mmol–1, respectively. The threshold values are useful to provide theoretical reference for achieving smart irrigation in the North China Plain.



2002 ◽  
Vol 159 (8) ◽  
pp. 891-898 ◽  
Author(s):  
Qingwu Xue ◽  
Madhavan Soundararajan ◽  
Albert Weiss ◽  
Timothy J. Arkebauer ◽  
P. Stephen Baenziger


2012 ◽  
Vol 63 (1) ◽  
pp. 67-76 ◽  
Author(s):  
Agnieszka Pszczółkowska ◽  
Gabriel Fordoński ◽  
Tomasz Kulik ◽  
Jacek Olszewski ◽  
Krystyna Płodzień ◽  
...  

The present pot experiment studied the effect of different soil moisture contents (60 - 70% CWC (capillary water capacity) - control; 30 - 35% CWC - water stress) on buckwheat productivity, the gas exchange parameters and health of buckwheat nuts. It was found that water deficit affected adversely certain biometric features investigated (plant height, number of nuts per cluster) and caused a decrease in seed weight per plant. It was also shown that water stress reduced the values of the investigated gas exchange parameters (photosynthesis rate, transpiration rate, intercellular-space CO<sub>2</sub> concentration, and stomatal conductance) relative to the control treatment. Different soil moisture contents did not have a clear effect on fungal colonization of seeds. The multiplex PCR assays did not enable the detection of the genes responsible for mycotoxin synthesis. Under water deficit conditions, an increase was found in the content of albumin and globulin fractions as well as of glutelin fractions.





HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 501d-501
Author(s):  
Jonathan N. Egilla ◽  
Fred T. Davies

Six endomycorrhiza isolates from the Sonoran Desert of Mexico [Desert-14(18)1, 15(9)1, 15(15)1, Palo Fierro, Sonoran, and G. geosporum] were evaluated with a pure isolate of Glomus intraradices for their effect on the growth and gas exchange of Hibiscus rosa-sinensis L. cv. Leprechaun under low phosphorus fertility (11 mg P/L). Rooted cuttings of Hibiscus plants were inoculated with the seven mycorrhiza isolates and grown for 122 days. Gas exchange measurements were made on days 26, 88, and 122 after inoculation, and plants were harvested on day 123 for growth analysis. Plants inoculated with the seven isolates had 70% to 80% root colonization at harvest. Plants inoculated with G. intraradices had significantly higher leaf, shoot and root dry matter (DM), leaf DM/area (P ≤ 0.05) than those inoculated with any of the six isolates, and greater leaf area (LA) than Desert-15(9)1 and 15(15)1. Uninoculated plants had significantly lower leaf, shoot, root DM, leaf DM/area and LA (P ≤ 0.05) than the inoculated plants. There were no differences among the seven isolates in any of the gas exchange parameters measured [photosynthesis (A) stomatal conductance (gs), the ratio of intercellular to external CO2 (ci/ca), A to transpiration (E) ratio (A/E)]. The relationship between inoculated and uninoculated plants in these gas exchange parameters were variable on day 122 after inoculation.



Plants ◽  
2021 ◽  
Vol 10 (2) ◽  
pp. 311
Author(s):  
Vegas Riffle ◽  
Nathaniel Palmer ◽  
L. Federico Casassa ◽  
Jean Catherine Dodson Peterson

Unlike most crop industries, there is a strongly held belief within the wine industry that increased vine age correlates with quality. Considering this perception could be explained by vine physiological differences, the purpose of this study was to evaluate the effect of vine age on phenology and gas exchange parameters. An interplanted, dry farmed, Zinfandel vineyard block under consistent management practices in the Central Coast of California was evaluated over two consecutive growing seasons. Treatments included Young vines (5 to 12 years old), Control (representative proportion of young to old vines in the block), and Old vines (40 to 60 years old). Phenology, leaf water potential, and gas exchange parameters were tracked. Results indicated a difference in phenological progression after berry set between Young and Old vines. Young vines progressed more slowly during berry formation and more rapidly during berry ripening, resulting in Young vines being harvested before Old vines due to variation in the timing of sugar accumulation. No differences in leaf water potential were found. Young vines had higher mid-day stomatal conductance and tended to have higher mid-day photosynthetic rates. The results of this study suggest vine age is a factor in phenological timing and growing season length.



2015 ◽  
Vol 105 (6) ◽  
pp. 738-747 ◽  
Author(s):  
Gisele Pereira Domiciano ◽  
Isaías Severino Cacique ◽  
Cecília Chagas Freitas ◽  
Marta Cristina Corsi Filippi ◽  
Fábio Murilo DaMatta ◽  
...  

Rice blast, caused by Pyricularia oryzae, is the most important disease in rice worldwide. This study investigated the effects of silicon (Si) on the photosynthetic gas exchange parameters (net CO2 assimilation rate [A], stomatal conductance to water vapor [gs], internal-to-ambient CO2 concentration ratio [Ci/Ca], and transpiration rate [E]); chlorophyll fluorescence a (Chla) parameters (maximum photochemical efficiency of photosystem II [Fv/Fm], photochemical [qP] and nonphotochemical [NPQ] quenching coefficients, and electron transport rate [ETR]); concentrations of pigments, malondialdehyde (MDA), and hydrogen peroxide (H2O2); and activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), glutathione reductase (GR), and lypoxigenase (LOX) in rice leaves. Rice plants were grown in a nutrient solution containing 0 or 2 mM Si (−Si or +Si, respectively) with and without P. oryzae inoculation. Blast severity decreased with higher foliar Si concentration. The values of A, gs and E were generally higher for the +Si plants in comparison with the −Si plants upon P. oryzae infection. The Fv/Fm, qp, NPQ, and ETR were greater for the +Si plants relative to the −Si plants at 108 and 132 h after inoculation (hai). The values for qp and ETR were significantly higher for the –Si plants in comparison with the +Si plants at 36 hai, and the NPQ was significantly higher for the –Si plants in comparison with the +Si plants at 0 and 36 hai. The concentrations of Chla, Chlb, Chla+b, and carotenoids were significantly greater in the +Si plants relative to the –Si plants. For the –Si plants, the MDA and H2O2 concentrations were significantly higher than those in the +Si plants. The LOX activity was significantly higher in the +Si plants than in the –Si plants. The SOD and GR activities were significantly higher for the –Si plants than in the +Si plants. The CAT and APX activities were significantly higher in the +Si plants than in the –Si plants. The supply of Si contributed to a decrease in blast severity, improved the gas exchange performance, and caused less dysfunction at the photochemical level.



2002 ◽  
Vol 53 (369) ◽  
pp. 737-746 ◽  
Author(s):  
Tracy Lawson ◽  
Jim Craigon ◽  
Colin R. Black ◽  
Jeremy J. Colls ◽  
Geoff Landon ◽  
...  


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