2002—2021年西藏中西部车前物候对气象条件驱动的响应

Response of Plantago asiatica Phenology to Meteorological Conditions in West-central Tibet from 2002 to 2021

探讨日喀则车前物候变化及其与气象条件的关系,旨在为气候变暖背景下西藏植被物候变化的研究提供支撑。基于2002—2021年西藏中西部日喀则站车前物候期和逐月平均气温、最高气温(T_(max))、最低气温(T_(min))、相对湿度(RH)、降水量(Pr)和日照时数(S)等资料,采用线性回归、Pearson相关系数和偏最小二乘法(PLS)回归等方法对车前物候期变化及与气象因子的关系进行研究。结果表明:(1)2002—2021年西藏中西部车前各物候期均呈显著推迟趋势,平均每10年推迟8.96~38.63 d,以种子全熟期推迟的最为明显;生长季长度呈弱的延长趋势(1.03 d/10 a)。(2)西藏中西部1月Tmin降低、3月S和11月RH减少,以及11月Tmax显著升高,是车前物候期显著推迟的主要原因。车前展叶始期和黄枯普期对气温的响应速率分别为3.41、4.37 d/℃。

The phenology changes of Plantago asiatica(PA)and their relationship with meteorological conditions were investigated in Shigatse,aiming to provide support for the study on the vegetation phenological changes in Tibet under the background of climate warming.Based on the data of PA’s phenology and monthly mean temperature,maximum temperature(T_(max)),minimum temperature(T_(min)),relative humidity(RH),precipitation(Pr)and sunshine duration(S)in Shigatse of west-central Tibet from 2002 to 2021,the change of PA’s phenophase and its relationship with meteorological factors in Shigatse were studied by the methods of linear regression,Pearson correlation coefficient and partial least regression(PLS).The main results showed that:(1)the phenophases of PA had been significantly delayed in west-central Tibet from 2002 to 2021,with rates ranging from 8.96 to 38.63 days per decade,among which the changing rate of seed full maturity date was the most obvious with the highest value.In contrast,the length of growth season had prolonged slowly at a rate of 1.03 days per decade.(2)The significant delay in the phenology of PA in west-central Tibet could be mainly attributed to the decrease of Tmin in January,the reducing of S in March and RH in November,and the significant increase of Tmax in November.The response rates to temperature were 3.41 and 4.37 d/℃in the first leaf expansion date and common leaf withering date of PA,respectively.