昼夜不对称增温对西藏冬青稞生长特性和产量的影响

Effects of Simulated Diurnal Asymmetrical Warming on the Growth Characteristics and Grain Yield of Winter Highland Barley in Tibet

青稞是藏族人民的主要食粮,青藏高原昼夜不对称增温明显,为了降低这种不对称增温对藏区未来粮食安全预测存在的不确定性,本研究在拉萨农业生态试验站以冬青一号为试验材料,采用FATI(Free Air Temperature Increase)田间开放式增温系统进行了为期两个生长季节(即2018–2019和2019–2020年)的昼夜不对称增温试验(即全天增温AW、白天增温DW、夜间增温NW和对照CK),以期探讨不对称增温对西藏冬青稞生长特性和产量的影响。结果表明:与对照相比,三种不同增温处理对冬青稞的物候期的影响显著,均导致各物候期提前,全生育期缩短,影响程度表现为AW>NW>DW,并且不同增温处理均使得冬青稞从播种到抽穗期的间隔缩短,抽穗期到完熟期间隔增加,AW效果最为明显,且达到统计显著水平(P<0.05);在生长前中期,冬青稞地上生物量和株高在不同增温影响下均有提高的趋势,生长后期,NW处理明显高于其他处理。此外,增温使得完熟期叶和茎鞘的分配比重下降,根和穗的分配比上升;AW、NW和DW增温处理产量两年平均提高了16.4%、24.6%和9.5%,其中2019–2020年NW处理较对照达到显著水平(t=–2.541,P=0.026);产量构成方面,有效穗数和千粒重有提高的趋势,每穗粒数除AW处理外有提高的趋势,穗长和结实率除NW处理外有降低的趋势。因此,昼夜不对称增温对西藏冬青稞的影响不同。

There has been an obvious diurnal asymmetrical warming effect as a result of the overall climate warming in the Tibetan Plateau. To reduce the uncertainty caused by the diurnal asymmetrical warming effect on future food security predictions in the Tibetan Plateau, this study used winter highland barley(var. Dongqing No. 1)for the experimental materials, and the FATI(Free Air Temperature Increase) field open heating system to carry out a simulated diurnal asymmetrical warming experiment(AW: All-day warming, DW: Daytime warming, NW:Nighttime warming, CK: Control) for two growing seasons(2018–2019 and 2019–2020) at the Lhasa Agroecosystem Research Station. The growth characteristics and yield of Tibetan winter highland barley were investigated in this study. Compared to the control, all the AW, DW and NW treatments had significant effects on the phenological period of winter highland barley, with the advancement of the phenological phase and shortening of the whole growth period. The degree of influence was AW>NW>DW, and all the AW, DW and NW treatments shortened the interval from sowing to heading of winter highland barley and increased the interval from heading to maturity. The effect on the phenological phase was the most obvious for AW and reached a statistically significant level(P<0.05).During the generative growth phase, the biomass above-ground and plant height of winter highland barley had an increasing tendency under the different warming conditions. In the late growth period, the biomass above-ground and plant height of the NW treatment were significantly higher than those of the other treatments. In addition, the warming caused a decrease in the dry matter distribution proportions of leaves and stems at the mature stage, and an increase in the distribution ratios of roots and spikes;and the AW, NW and DW treatments increased grain yields by 16.4%, 24.6% and 9.5%, respectively, on average in the two years. The increasing effect on grain yields of the NW treatment reached a significant level compared with the control in 2019–2020(t=–2.541, P=0.026). In terms of yield composition, the effective spike number and 1000-grain weight tended to increase. The grain number per spike tended to increase, except for the AW treatment, while panicle length and seed setting rate tended to decrease, except for the NW treatment. Therefore, the effects of different simulated diurnal asymmetrical warming treatments on the growth characteristics and yield of winter highland barley were variable in the Tibetan Plateau.