INVASION OF BASSENDEAN DUNE BANKSIA WOODLAND BY PHYTOPHTHORA-CINNAMOMI
INVASION OF BASSENDEAN DUNE BANKSIA WOODLAND BY PHYTOPHTHORA-CINNAMOMI
复制标题
DOI：
10.1071/bt9940725
复制
发表时间：
1994-01-01
影响因子：
1.1
通讯作者：
SHEARER, BL
中科院分区：
文献类型：
--
作者：
HILL, TCJ;TIPPETT, JT;SHEARER, BL
研究了西澳大利亚州珀斯北部巴森丹沙丘系统班克西亚林地肉桂疫霉的传播速度和机制。航空照片被用来测量35年来疾病在前线超过5公里的传播情况。上坡坡位锋面分别在1.01和1.13m年(-1)下坡和上坡，而低洼位置锋面在1.30和1.20m年(-1)分别下移和抬升(与地下水位流向相反)。低洼地区的锋面比上坡地区的锋面扩散得快得多。对复盖共显性的21株枯死植物的根系进行了2m深度的挖掘，发现28%的一级根(3.9根/株)被侵染。对根部感染比例的评估表明，无论是在上坡还是在排水平坦的地方，根部感染的程度都明显偏离了沿剖面的均匀分布。在距含水层6~40m的沙丘坡地上的14株树木中，21~40 cm土层的根部感染率高于预期，而1m以下的根部感染率低于预期，73%的病根位于土壤表层40 cm。在距含水层2~3m的排涝平地上的7棵树上，21~60 cm土层和1m以下的根部的侵染率较高，尽管排涝平地树木的地下水位附近有肉桂疫霉菌的活动，但该病在所有景观位置的缓慢而稳定的传播表明，真菌入侵的主要方式是通过敏感植被的根。没有发现游动孢子扩散引起的疾病加速传播的证据。
The rate and mechanism of the spread of Phytophthora cinnamomi in Banksia woodland of the Bassendean Dune system north of Perth, Western Australia was studied. Aerial photographs were used to measure the spread of disease in fronts longer than 5 km over 35 years. Fronts in upper slope positions moved downhill and uphill at 1.01 and 1.13 m year(-1), respectively, while fronts in low-lying positions moved downgrade and upgrade (with and against the direction of water table flow) at 1.30 and 1.20 m year(-1), respectively. Fronts in low-lying areas spread significantly faster than those on upper slopes. Excavations to 2 m depth of the root systems of 21 dying plants of Banksia attenuata R.Br., an overstorey co-dominant, revealed that 28% (3.9 roots/tree) of all first-order roots were infected. Assessment of the proportion of roots infected revealed a significant (P < 0.01) departure from uniform distribution of disease down the profile in both upper slope and drained flat sites. In 14 trees on dune slopes, 6-40 m above the aquifer, infection rate was higher than expected in roots lying at 21-40 cm depth, but lower than expected in roots below 1 m. Seventy three percent of infected roots lay in the top 40 cm of soil. In seven trees on a drained flat, 2-3 m above the aquifer, infection rate was high in the 21-60 cm horizon and also in roots below 1 m. Even though Phytophthora cinnamomi was active in the vicinity of the water table in trees on drained flats, the slow, steady spread of the disease in all landscape positions suggested that the primary mode of fungal invasion was through roots of susceptible vegetation. No evidence was found of accelerated spread of disease caused by the dispersal of zoospores.