广西南部马尾松木质部年内生长动态及对气候响应规律

Intra-annual xylem formation dynamics of Pinus massoniana in southern Guangxi and its response to climate

为探究广西壮族自治区凭祥市人工纯林马尾松(Pinus massoniana)木质部的年内生长动态及其对气候的响应规律,本研究利用微树芯采样法对9棵马尾松的木质部进行连续两年监测(2022~2023年),采用Gompertz模型拟合木质部细胞年内生长动态,并利用线性混合模型分析木质部生长速率与气候因子,包括温度(最高温、最低温和平均温)、降雨量、相对湿度、光合有效辐射和日照时长的相关关系。结果表明:1)广西南部马尾松木质部细胞在3月初期开始生长,于5月底达到生长速率峰值,之后细胞生长速率逐渐下降,在12月仍旧保持低速缓慢的生长;2)马尾松木质部生长速率与采样前7天、10天、15天的最高温、最低温和平均温和采样当天日照时长均呈极显著的正相关关系(p<0.001),与采样前7天、10天、15天的光合有效辐射总量均呈显著的正相关关系(p<0.05),与采样前7天、10天、15天的相对湿度和降雨量的相关关系不显著(p>0.05)。研究结果揭示了温度、光合有效辐射以及日照时长对广西南部马尾松的木质部年内生长有促进作用,为未来气候变化背景下马尾松的经营管理提供了一定的理论基础。

In order to explore the intra-annual xylem growth dynamics of Pinus massoniana in plantation forest and its response to climate in Pingxiang City,Guangxi Zhuang Autonomous Region,we selected nine 63-year old P.massoniana at the tropical forestry experiment center(22°02'N,106°51'E),sampled a total of 414micro-cores biweekly during 2022 and 2023,and obtained the daily climatic date including temperature(maximum,average,and minimum),precipitation,relative humidity,photosyntetically active radiation,and sunshine duration of the study site.The Gompertz model was used to fit the intra-annual xylem formation dynamics of P.massoniana and mixed linear model was employed to elucidate the relationship between xylem growth rate and climatic factors.The results showed that:(1)The xylem cells of P.massoniana in southern Guangxi began to grow around the beginning of March,and reached the peak at the end of May to the beginning of June.After that,the cell growth rate gradually decreased,and maintained a slow growth in December.(2)The growth rate of xylem was significantly positively correlated with the maximum,minimum,and average temperature on 7,10 and 15 days prior to the sampling date and the sunshine duration on the sampling date(p<0.001).Also,it was significantly positively correlated with the photosyntetically active radiation on 7,10 and 15 days prior to the sampling date(p<0.05),and was not significantly correlated with the relative humidity and precipitation on 7,10 and 15 days prior to the sampling date(p>0.05).These results revealed that temperature,photosyntetically active radiation,and sunshine duration could promote the intra-annual xylem formation dynamics P.massoniana and provided a theoretical basis for the management of P.massoniana under the background of future climate change.