[Effects of elevated ozone concentration on wheat grain protein components with FACE system].

In 2006-2009, a Free-Air Controlled Enrichment (FACE) system was applied to study the effects of elevated ozone concentration ([O3]) on the grain protein components and their dynamics of four winter wheat varieties Yannong 19, Yangmai 16, Yangmai 15, and Yangfumai 2. Two levels of [O3] were installed, i. e., ambient level (CK-O3) and 50% higher than the ambient level (E-O3). With the increase of [O3], the grain protein content of the varieties increased, with the increment being 7.55% - 16.37% (2006 - 2007), 4.93% - 22.63% (2007 - 2008), and 2.29% - 17.65% (2008 - 2009) in the three years, respectively, and the differences between treatments, varieties, and years being all significant. Adversely, the grain protein yield was decreased significantly by 1.83% - 11.64% (2006 - 2007), - 0.41% - 24.22% (2007 - 2008), and -1.90% - 15.81% (2008 - 2009), respectively in the three years. The contents of four grain protein components (albumin, globulin, gliadin, and glutenin) were significantly higher under E-O3 than under CK-O3, and the differences between treatments, varieties, and years were significant, except the albumin and glutenin contents between treatments.

[Photosynthetic damage induced by elevated O3 in two varieties of winter wheat with free air controlled enrichment approach].

O3-FACE (ozone-free air controlled enrichment) platform has been established for observing the photosynthetic damage induced by elevated O3 in functional leaves of two winter wheat (Tritcium aestivum L.) varieties (Yangmai 16 and Yannong 19) during grain filling stage. The results showed that the response trend of all the parameters was similar: (1) The net photosynthetic rate (Pn) decreased gradually and after 35 days of O3 treatment, Pn decreased by 56.21% and 21.82% for Yannong 19 and Yangmai 16, respectively. (2) Chlorophyll fluorescence kinetics parameters changed as decreased in Fv/Fm (maximal photochemical efficiency of PS II in the dark), qp (photochemical quenching), Phiexe (excitation capture efficiency of PS II or intrinsic PS II efficiency), PhiPSII (actual photochemical efficiency of PS II in the light), and increased in NPQ (non-photochemical quenching); Energy distribution parameters changed as rose in % D (fraction of light absorbed in PS II that is dissipated in the PS II antenna), reduced in % P (fraction of light absorbed that is used in photochemistry), and no significant changed in % X (fraction of light absorbed that is not used or dissipated in the PS II antenna). After 35 days of O3 treatment, the actual photochemical efficiency of PS II of Yannong 19 and Yangmai 16 were reduced by 24.42% and 9.97%, respectively.(3) It was declined in Chlt/Car (total chlorophyll content/carotinoid content) while the ratio of Chla/Chlb (chlorophyll a content/chlorophyll b content) was increased. There was a growth in Mg2+, Ca2+-ATPase, activities and ATP contents in chloroplast. The extent of variation in the above parameters and the differences between the two varieties were enlarged as the O3 treatment time increasing and it could be found a more serious damage effect in Yannong 19 than that of in Yangmai 16. In conclusion, the responses of the capacities of defense and repair systems of the two varieties to elevated O3 were reflected by increase in heat dissipation, changes in contents and composition of photosynthetic pigments, and enhancement in the ATP (ATP enzyme) activities in chloroplast. With the time of O3 treatment elongating, there was an accumulation effect of 03 damage to wheat and a great different tolerance between the two varieties was observed.