Disease development in Ficus carica plants after inoculation with Ceratocystis ficicola. (1) Relationship between xylem dysfunction and wilt symptoms
Disease development in Ficus carica plants after inoculation with Ceratocystis ficicola. (1) Relationship between xylem dysfunction and wilt symptoms
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DOI：
10.3186/jjphytopath.82.301
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发表时间：
2016-11-01
期刊：
影响因子：
--
通讯作者：
Kuroda, K.
中科院分区：
文献类型：
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作者：
Morita, T.;Jikumaru, S.;Kuroda, K.
Ceratocystis ficicola 在日本的许多无花果园中引起严重的枯萎病。为了阐明该疾病症状发展的过程，我们宏观地检查了外部症状并评估了接种无花果树的无花果植物的木质部汁流。外部症状分类如下：(1)无外部症状(NS)，(2)叶枯病(LW)，和(3)死亡(D)。在相对狭窄的范围内观察到C. ficicola在茎段上的子囊发育，每个NS植物的接种位点上方和下方各5厘米。在具有 LW 的植物中，在接种位点上方和下方 10 厘米的更广泛范围的片段上观察到子囊发育。在 D 植物中，在比 LW 植物更窄范围的片段上观察到子囊发育。在 NS 植物中，在接种位点附近、接种位点上方 5 cm 和下方 10 cm 的范围内观察到木质部变色。每个 NS 植物中木质部变色的最大百分比（变色面积/横截面积）范围为 1.3% 至 16.4%。变色范围扩大到接种位点上方15厘米和下方10厘米，每个LW植株木质部变色的最大值为16.5％至52.4％。在每个 D 植物中观察到与 LW 中类似的变色。水电导率以被酸性品红溶液染成粉红色的茎被根部吸收的百分比来评估。 NS植物的水电导率与对照植物的水电导率相似。每个 LW 植物的水电导率均低于 NS，切下的茎段上最小染成粉红色的面积小于 4.6%。 D 植物中的染色区域几乎无法辨认。 LW 或 D 植物的叶子没有任何染色区域。无花果树接种 C. ficicola 后出现的症状可解释如下： (1) 木质部变色从接种部位开始扩大，与 C. ficicola 分布范围的扩大相对应。 (2)木质部变色与木质部功能障碍相关。 (3)当接种部位附近截面木质部电导率下降到一定阈值时，向叶片的供水量减少，引起叶片萎蔫。 (4) 广泛的木质部功能障碍导致树木死亡。
Ceratocystis ficicola causes serious wilt disease in many fig orchards in Japan. To elucidate the process of symptom development in the disease, we macroscopically examined external symptoms and assessed xylem sap flow in fig plants inoculated with C. ficicola. External symptoms were classified as follows: (1) no external symptoms (NS), (2) leaf wilt (LW), and (3) dead (D). Perithecial development of C. ficicola on stem segments was observed within a relatively narrow range, 5 cm above and below the inoculation site of each NS plants. In plants with LW, perithecial development was observed on segments from a wider range, 10 cm above and below the inoculation sites. In D plants, perithecial development was observed on segments from a narrower range than that of the LW plants. Xylem discoloration was observed near the inoculation site, in the range of 5 cm above and 10 cm below the inoculation site, in NS plants. The maximum percentage of xylem discoloration (discolored area/cross-section area) in each NS plants ranged from 1.3 to 16.4%. The range of discoloration extended 15 cm above and 10 cm below the inoculation site, and the maximum value of the xylem discoloration in each LW plants ranged from 16.5 to 52.4%. Discoloration similar to that in LW was observed in each D plants. Water conductivity was evaluated as the percentage of stem dyed pink with acid fuchsin solution absorbed by the roots. Water conductivity by NS plants was similar to that in the controls. Water conductivity was lower in each LW plant than in the NS, and the minimum dyed pink area on cut stem segments was less than 4.6%. The dyed area was barely recognizable in D plants. Leaves of LW or D plants did not have any dyed areas. Symptom development after inoculation of fig trees with C. ficicola can be explained as follows: (1) Xylem discoloration expands from the inoculation site corresponding to the expanding distribution of C. ficicola. (2) Xylem discoloration is correlated with xylem dysfunction. (3) When conductivity of the xylem falls to a certain threshold value in a cross section near the inoculation site, the water supply to leaves decreases, causing leaf wilting. (4) Extensive xylem dysfunction results in tree death.