Effects Of Asymmetric Warming On Yield And Quality Of Winter Wheat

Climate warming is already an indisputable fact, and the global temperature is rising asymmetrically with the daily minimum temperature rising faster than the daily. Winter wheat is one of the main food crops in China, and it is greatly influenced by the warming of the climate. Therefore, this experiment used Xu mai31 and Yang mai13 as mate rials, using the open field warming system Free-air Temperature Increase (FATI) system in winter wheat field in Nanjing University of Information Science & Technology during 2013 to 2014,by designing different warming duration, which is Day Warming (DW:warmed from 06:00 to 18:00, 2.0℃), Night Warming (NW:warmed from 18:00 to 06:00,2.0℃), Day-night Symmetric Warming (DNSW:warmed from 06:00 to 18:00,2.0℃;warmed from 18:00 to 06:00,2.0℃), Day-night Asymmetric Warming(DNAW:warmed from 06:00 to 18:00,1.0℃;warmed from 18:00 to 06:00,3.0℃) to simulate 4 warming scenarios of climate warming to simulalate the effect of warming climate on the yield and quality of winter wheat. The main results were as follows:1. Effects of asymmetric warming on growth and development of winter wheat. DW, NW, DNSW and DNAW significantly advanced the growth period of winter wheat, shorten the days from sowing to physiological jointing, especially in DNAW.In addition, DW, NW, DNSW and DNAW reduced the effective tillering and the LAI after anthesis. Overall, under the conditions of warming,the decline range of effective tillering on Xu mai 31 was 4.97%-11.98% and Yangmai 13 was 3.53%-7.05%,the decline range of LAI after anthesis on Xu mai 31 was 10.58%-15.71% and Yangmai 13 was 8.38%-15.26%, which showed that the effect of warming on the strong gluten winter wheat was was more easily affected than that on the weak gluten.2. Effects of asymmetric warming on dry matter accumulation and yield of winter wheat. DW, NW, DNSW and DNAW decreased the dry matter accumulation of winter wheat in the mature period, especially in DNAW. The formation of winter wheat yield is mainly from the post anthesis dry matter translocation. DW, NW, DNSW and DNAW reduced the dry matter translocation, the two varieties of the dry matter translocation from large to small sort were CK>DW>DNSW>NW>DNAW, especially in DNAW. Spikes per m2, kernels per spike and kernel weight are the main components of winter wheat grain yield, DW, NW, DNSW and DNAW decreased Spikes per m2, kernels per spike, kernel weight, yield and harvest index, and the yield of two varieties from large to small sort were CK>DW>DNSW>NW>DNAW, especially in DNAW. Overall, under the conditions of warming,the decline range of yield on Xu mai 31 was 5.64%-14.25% and Yangmai 13 was 5.14%-11.15%,which showed that the effect of warming on the strong gluten winter wheat was was more easily affected than that on the weak gluten.3. Effects of asymmetric warming on carbon and nitrogen metabolism and quality of winter wheat. DW, NW, DNSW and DNAW decreased the content of total sugar and sucrose content in stems and leaves of winter wheat,which as well as decreased the content of branched starch and total starch in grain, especially in DNAW.However, warming increased the content of nitrogen content in stems and leaves of winter wheat, which as well as increased the content of amylose starch,albumin, globulin, gliadin and total protein in grain, especially in DNAW. Overall, under the conditions of warming,the decline range of total starch on Xu mai 31 was 4.86%-8.03 and Yangmai 13 was 4.30%-7.48%,which showed that the effect of warming on the strong gluten winter wheat was was more easily affected than that on the weak gluten; the increase range of total protein on Xu mai 31 was 7.19%-12.44 and Yangmai 13 was 8.49%-14.20%,which showed that the effect of warming on the weak gluten winter wheat was was more easily affected than that on the strong gluten.4. Effects of asymmetric warming on Photosynthetic Characteristics and antioxidant system of winter wheat. DW, NW, DNSW and DNAW decreased the SOD activity, POD activity and CAT activity of flag leaf, but the content of MDA was increased.Finially, DW, NW, DNSW and DNAW accelerated the senescence of flag leaf,decreased the net photosynthetic rate and chlorophyll content. Overall, under the conditions of warming,the decline range of the net photosynthetic rate on Xu mai 31 was 9.05%-14.34% and Yangmai 13 was 8.91%-11.15%,which showed that the effect of warming on the strong gluten winter wheat was was more easily affected than that on the weak gluten; the decline range of the chlorophyll content on Xu mai 31 was 5.78%-12.58% and Yangmai 13 was 5.65%-11.98%,which showed that the effect of warming on the strong gluten winter wheat was was more easily affected than that on the weak gluten.