巨尾桉种质胶丸常温保存条件研究

Studies on the Requirements of Conservation of EucalyptusGermplasm Encapsulated in Alginate Beads at Room Temperature

巨尾桉组培苗的节段（包括茎尖、第１和第２节段）用海藻酸钠包成胶丸，胶丸埋于无营养的琼脂培养基内，在２５～３０℃，１５００１ｘ（１０～１４）一般培养室条件下，保存１０个月时，再生率可达５２％，研究证实这是一种可行的种质保存方法。光照是保存的必要外部条件。低浓度（１．５％～２％）海藻酸钠比高浓度（５．５％）有利于维持种质的活力。胶丸基液筛选结果表明，蔗糖浓度是制约种质活力和再生率的关键因子，低浓度蔗糖（０．５％）和无机盐表现出有益影响，蔗糖易导致胶丸内节段变黑、降低种质活力和再生率；保存期间，胶丸颜色由绿逐渐转白或转黑，是胶丸种质丧失活力和再生能力的两个主要表现过程；由此显示，可用种质胶丸颜色估测保存种质的活力状态。

Eucalyptus grandis × E.urophylla microcuttings in vitro were encapsulatedwith alginate as the gel bead style and maintained in agar medium without nutrition.It wasfound that this style was a suitable method for the conservation of Eucalyptus germplasm.Regenerative rates of shoot were 52%after ten months’conservation.High vigor ofgermplasm was observed in low concentration(1.5%～2.0%)of encapsulated sodium algi-nate.The tests of basic components supplemented in the alginate by single factor or multiplefactors orthogonal design showed that sucrose concentration was the key factor limiting thevigor and regenerative rate of germplasm. Low concentration of sucrose(0.5%)and mineralsshowed the benefited effect,but 5.5%sucrose induced blackening of microcuttings,decreasedthe vigor,and decreased the regenerative rate of germplasm.During the conservation period,changes of alginate bead colour from green to white or to black were the two main apparentindicators of losing vigor and regeneration capacity.The results suggest that apparent colourof gel bead might be used to estimate the vigor status of conserved germplasm.Light was anecessary factor for conservation of the encapsulated culture germplasm.