柑橘立枯病病原在罹病柑橘樹之分佈

Distribution of Likubin Pathogen in likubin-affected Citrus Plants

黃秋雄(Chiou-Hsiung Huang)

《中華農業研究》 28卷1期 (1979/03) Pp. 29-33

https://doi.org/10.29951/JARC.197903.0005

摘要

立枯病複合病原經芽接於二年生健全椪柑苗上，經六個月後切取根、莖及嫩莖等不同部位組織檢定，就二年觀察所得結果，發現立枯病菌質體病原已分佈於整棵柑橘苗中，但病原存在於嫩莖之機會較多，根組織則較少。立枯病中之另一病原即Tristeza病毒則分佈較爲均勻。
若自發病初期僅1~2枝條呈現立枯病病徵之罹病樹採取無病徵枝條，經檢定結果發病甚少。自發病中期或後期者，則無病徵枝條潛伏立枯病病原之機會較多。此種現象顯示立枯病病原初期可能僅存在於呈現病徵之枝條，然後緩慢移動於整棵植株。病穗採自經抗生素四環素灌注後之罹病樹，發病率略爲降低，可能係受藥劑影響，使病原分佈不均。

並列摘要

The cause of citrus likubin is considered to be a pathogen complex, both tristeza virus and mycoplasma-like organism (MLO) are associated with the disease, but MLO is believed a main component in producing likubin symptoms in the fields. In this study it mainly discussed the distribution of MLO in likubin-affected citrus trees.
An two-year-old Ponkan seedlings were inoculated with likubin pathogen complex. After a period of 6 months, different plant parts including root, stem and young shoot were taken from inoculated seedlings and indexed an indicator plants. The results indicated that MLO pathogen existed in different plant parts, it distributed more even in young shoot than in root. Contrary, tristeza virus was distributed very even either in stem or in root tissues.
Budwood collected from apparently healthy branches of diseased trees failed to produced likubin symptoms or could only develop lower percentage of transmission. Diseased scions taken from affected trees treated with tetracycline solution also decrease the percentage of transmission. The tetracycline solution injected into diseased trees orobably suppressed the symptom development and influenced the distribution of MLO pathogen.
The overall results clearly indicate that MLO is uneven distributed in diseased trees, especially in partially affected trees. It may be confined to the diseased branches showing symptoms or absence from many portion of the affected trees.