Fine root dynamics in a Japanese cedar (Cryptomeria japonica) plantation throughout the growing season
Fine root dynamics in a Japanese cedar (Cryptomeria japonica) plantation throughout the growing season
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DOI：
10.1016/j.foreco.2006.01.004
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发表时间：
2006-04-15
影响因子：
3.7
通讯作者：
Konôpková, Z
中科院分区：
文献类型：
--
作者：
Konôpka, B;Noguchi, K;Konôpková, Z
为了阐明植物吸收水分和养分的关键成分——细根和根尖的动态，在日本关东平原北部的一个28年的杉木人工林中进行了连续的土壤芯取。2004年3月上旬至11月中旬，每6周测定1 mm以下细根的生物量、坏死质量、白色根尖和棕色根尖数量。在不同的采样周期内，还估算了细根及其尖端的产量和死亡率。细根质量和根尖数量在最上层土层最大，且呈现季节变化。细根生物量在夏末（8月）前呈上升趋势，而后呈下降趋势，坏死根生物量在夏季低于其他季节。在0 ~ 15 cm土层和15 ~ 35 cm土层中，初夏（6月）和秋季（10月）白色根尖数量最多。夏末至秋季（8 - 10月）褐根尖数量高于其他采样期。这些结果表明，日本雪松在夏季具有很高的水分和养分吸收潜力，尽管秋季的潜力也相当大。细根干物质产量在夏季（6 ~ 8月）达到高峰，但土壤最下层（25 ~ 35 cm深）除外。表层土壤白根尖产量也在仲夏（7 - 8月）达到高峰，而深层土壤的季节变化不明显。表层土壤细根生长在初夏（6 - 7月）停止，可能是由于干旱胁迫或碳主要分配到地上器官。夏末（3 ~ 8月）前细根死亡率较低，夏末（8 ~ 11月）后死亡率急剧上升。因此，杉木细根的产量和死亡率具有明显的季节变化。土壤深度似乎强烈影响季节动态，这表明外部条件，如土壤温度和湿度，以及树木的生理状态，在很大程度上影响了杉木的细根动态。(c) 2006 Elsevier B.V.版权所有
To elucidate the dynamics of fine roots and root tips, which are key components in water and nutrient uptake by plants, sequential soil coring was conducted in a 28-year-old Japanese cedar (Cryptomeria japonica) plantation in the northern part of the Kanto plain, Japan. Biomass, necromass, and the number of white and brown root tips of fine roots < 1 mm in diameter were determined every 6 weeks from early March to mid-November 2004. The production and mortality of fine roots and their tips between sampling periods were also estimated.Fine root mass and the number of root tips were largest in the uppermost soil layer and showed seasonal changes. Fine root biomass increased until late summer (August) and then declined, while necromass was lower in summer than in other seasons. The largest number of white root tips was observed in early summer (June) and in autumn (October) at a soil depth of 0-15 and 15-35 cm, respectively. The number of brown root tips was greater in late summer to autumn (August-October) than during other sampling periods. These results suggest that Japanese cedar has a high potential for water and nutrient uptake in summer, although the potential in autumn may also be considerable.The production of fine root dry matter peaked in summer (June-August), except in the lowest soil layer (25-35 cm deep). The production of white root tips in topsoil also reached a peak in mid-summer (July-August), whereas seasonal variation was unclear in deeper soil. Fine root production in the topsoil ceased during the early summer (June-July), probably due to drought stress or to the predominant allocation of carbon into aboveground organs. The mortality rates of fine roots were low until late summer (March-August), but sharply increased thereafter (August-November). Thus, the production and mortality of fine roots of Japanese cedar show clear seasonal changes. Soil depth, appears to strongly affect seasonal dynamics, suggesting that external conditions, such as soil temperature and moisture, together with the physiological status of the trees, substantially influence the fine-root dynamics of Japanese cedar. (c) 2006 Elsevier B.V. All rights reserved.