水稻體細胞癒合組織的來源與再分化的研究

Abstract

培養台南5號水稻根與莖尖於含2 mg/l 2,4-D的MS培養基(MSD)上，以誘導癒合組織的產生。將根與莖尖的癒合組織培養於NAA與kinetin不同濃度組成的培養基上，發現根癒合組織在NAA 0.5mg/l，kinetin 1mg/l與NAA 1 mg/l，kinetin 4 mg/l兩種組成有20％的莖芽分化率。莖尖癒合組織在NAA 0.5 mg/l，kinetin 2 mg/l上有20.7％的莖芽分化率。 培養不同生長狀況與不同部份的根於MSD上，由外觀發現癒合組織從根的根尖、側根尖端、側根原等具分生能力的地方長出癒合組織。進一步由根的組織切片中瞭解癒合組織係從根維管束鞘的側根起源體，及其內的薄壁細胞形成。並發現根癒合組織的初生形態及生長狀況與根原和根尖分生組織的生長形態相像。 莖尖癒合組織在MSD上繼代培養一次，第7天移至分化培養基上，第11?17天選擇有綠色區域出現的癒合組織做成組織切片，可以看到癒合組織中類根原、類尖端分生組織與擬分生組織塊的生長方式。並見到似莖尖、似葉原、類維管束與木質部等的器官再分化。

Roots and shoot tips of Oryza sativa L. Tainan 5 were cultured in MS basal medium containing 2 mg/l 2,4-D for callus induction. The callus was then transferred to medium containing various concentrations of NAA and kinetin for shoot redifferentiation. The percentage of shoot formation of root callus in the medium containing 0.5 mg/l NAA & 1 mg/l Kinetin, and 1 mg/l NAA & 4 mg/l Kinetin was found to be 20%. The percentage of shoot formation of shoot tip callus in the medium containing 0.5 mg/l NAA & 2 mg/l Kinetin was found to be 20.7%. In the external view, callus was originated from the root tips, lateral root tips and lateral root primordia. Microscopic observation on excised roots has shown that the process of callus formation includes two different phases, one is transformation of the lateral root primordia from the pericycle of the excised roots, and the other is the dedifferentiation of the parenchyma cells of the phloem and xylem. The histological study on callus revealed that the initial development of the root callus was very similar to the early process of the organization of root primordia. Shoot tip callus culturing in the shoot-forming medium for 11 to 17 days produced green areas on the callus surface which showed defined gross morphological characteristics relating to organogenesis. These green areas have been prepared for light microscopic study. It was observed that the peripheral and inside region of the callus showed structures resembling meristemoid, root primordia, root apical meristem and vascular bundle-like tissue. Shoot apex and leaf primordia-like structure rising from callus surface were also observed.