人工合成生長素， 丁酸 (IBA)，能有效地促進牛樟插穗不定根的誘發。在兩牛樟品系中，IBA在高發根率品系 (H107) 造成的效應，較低發根率品系 (L41) 快速。IBA處理5天後，H107處理組過氧化

Synthetic auxin, indole-3-butyric acid (IBA), effectively promoted the rooting in Cinnamomum kanehirae cuttings. The easy-to-root genotype, H107, responded to IBA much earlier than the difficult-to-root genotype, L41. On day 5, the POD activity significantly decreased in the IBA-treated tissues as compared with the control. Similar phenomenon was observed in extract of L41 genotype showing that IBA inhibited POD activity. In addition, the variation in POD activity corresponds to an inverse variation in the concentration of free IAA. The levels of IAA in H107 genotype increased dramatically in IBA-treated tissues on day 5; while, in L41 genotype, the raise of IAA in IBA-treated tissues was observed on day 20. Moreover, the lignin content in IBA-treated H107 cuttings decreased is quite correlated with the decline of the POD activity; yet the lignin content in L41 genotype cuttings was almost unchanged. Hence, we suggest that the inhibition on POD may lead to the redifferentiation processes induced by IBA, then produce the new root primordia during the formation of adventitious roots.

TABLE OF CONTENTS

Chinese abstract ------------------------------------- I

English abstract ------------------------------------- II

Table of contents ---------------------------------- III

List of tables and figures ------------------------- IV

Introduction ------------------------------------------ 1

Materials and Methods ----------------------------- 6

Results ---------------------------------------------- 11

Discussion ------------------------------------------ 15

Reference ------------------------------------------- 19

Tables and figures --------------------------------- 26


List of Tables and Figures

Table 1. Effect of indolic-3-butyric acid on the formation of adventitious roots in Cinnamomum kanehirae cuttings of easy-to-root genotype, H107 and difficult-to-root genotype, L41. -------------------------------------------------------------------------- 26

Fig. 1. Effect of indole-3-butyric acid on the peroxidase activity during the adventitious root formation in Cinnamomum kanehirae cuttings. ------------------------------------------------------------- 27

Fig. 2. Effect of indole-3-butyric acid on the activities of the peroxidase isozymes during the adventitious root formation of Cinnamomum kanehirae easy-to-root genotype cuttings, H107. -------------------------------------------------------------------------- 28

Fig. 3. Effect of indole-3-butyric acid on the activities of the peroxidase isozymes during the adventitious root formation of Cinnamomum kanehirae difficult-to-root genotype cuttings, L41. ---------------------------------------------------------------- 29

Fig. 4. HPLC chromatogram of extract from Cinnamomum kanehirae cuttings. ----------------------------------------------------------- 30

Fig. 5. Changes of IAA content in the extracts of Cinnamomum kanehirae cuttings. ---------------------------------------------- 31

Fig. 6. Effect of indole-3-butyric acid on the lignin content during the adventitious root formation in Cinnamomum kanehirae cuttings. ------------------------------------------------------------------------ 32

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