不同品种油茶细根时空分布动态

以赣无1、赣永5、长林4、长林40和赣447 等5个品种的油茶林为研究对象,采用微根管技术对0～40 cm土壤剖面的油茶细根进行了为期一年的观测,并分析了总根尖数(TRT)、平均根长密度(ARLD)、平均直径(ARD)的时空分布动态规律.结果表明: 2016年下半年,各品种的TRT和ARLD变化相对稳定,2017年上半年,各品种的TRT和ARLD变化幅度较大,尤其体现在赣无1与长林40中.赣无1的TRT和ARLD在2017年5月出现峰值,长林4的ARD在2017年3月出现峰值.赣无1的TRT和ARLD 以及长林4的ARD在整个观测期都显著大于其他品种.不同品种油茶细根在土层中的空间分布规律及动态变化存在明显差异,赣无1和赣447的细根主要分布在0～20 cm土层中,长林4和长林40的细根以20～40 cm土层居多,空间分布动态变化较其他3个品种稳定;赣永5的空间分布动态变化幅度较大,根量分布各土层无显著差异;长林4的ARD表现为20～40 cm土层>0～20 cm土层,其他品种的ARD在不同土层中无显著差异.赣无1的细根生物量最多,主要分布在上层;长林4的细根直径最粗,主要分布在下层.

Temporal and spatial distributions of fine roots of different varieties of Camellia oleifera

We examined fine root distribution dynamics at the depth of 0-40 cm soil profile for five varieties of Camellia oleifera, including “Ganwu 1”, “Ganyong 5”, “Changlin 4”, “Changlin 40” and “Gan 447”, in one year using minirhizotron technique. The temporal and spatial distribution characteristics of total root tip number (TRT), average root length density (ARLD) and average root diameter (ARD) were analyzed. The results showed that the TRT and ARLD changes of each variety were relatively stable in the second half of 2016, while there was a significant monthly fluctuation in the first half of 2017, especially for “Ganwu 1” and “Changlin 40”. The TRT and ARLD of “Ganwu 1” peaked in May 2017, while the ARD of “Changlin 4” peaked in March 2017. The TRT and ARLD values of “Ganwu 1” and the ARD value of “Changlin 4” were significantly greater than those of other varieties during the whole observation period. The spatial distribution and monthly dynamics of fine roots varied significantly among different varieties of Camellia oleifera. The fine roots were mainly distributed at the soil layer of 0-20 cm for “Ganwu 1” and“ Gan 447 ”, but at 20-40 cm for “ Changlin 4 ”and “ Changlin 40 ”. The latter two varieties had relatively stable spatial distribution and monthly dynamics of fine roots when compared to others. In contrast, the root biomass of “Ganyong 5” was not significantly different between both soil layers despite a large spatial variation. The ARD of “Changlin 4” was significantly larger at the soil layer of 20-40 cm than that of 0-20 cm. There was no significant difference in ARD between both soil layers for other varieties. In conclusion, within the five varieties, “Ganwu 1” had the greatest biomass of fine roots, which were mainly distributed in the upper soil layer, while “Changlin 4” had the largest diameter of fine roots, which were mainly distributed in the lower soil layer.