培養條件對報歲蘭根莖生長分化之影響及培植期間瓶內氣體之變化

Abstract

本研究探討培養基成分、乙烯相關藥劑等不同培植條件對報歲蘭根莖生長及分化之影響，以及根莖及芽體分化發育過程，瓶內二氧化碳及乙烯濃度的消長與生長分化之關係。期望尋求最佳培養條件，提高國蘭增殖速率、瓶苗品質及出瓶後生長，並作為國蘭瓶內生理研究之基礎。 白花報歲蘭及‘金華山’報歲蘭以蔗糖、葡萄糖、果糖、葡萄糖加果糖四種碳源處理，對根莖生長無顯著影響。在培養基氮素方面，根莖生長對氮素濃度需求較芽體生長分化高，白花報歲蘭以50.6 mM氮素濃度、‘金華山’以30.0 mM 氮素濃度對於根莖生長較佳。芽體生長分化則以14.6 mM氮素處理，芽體及根部鮮重累積較高。 觀葉型報歲蘭‘瑞寶’ × ‘光華蝶’根莖培養於根莖繁殖培養基及抽芽培養基，培養第4週至第12週所誘導之根莖及芽體快速增殖，此時瓶內二氧化碳濃度持續累積。於抽芽培養基培養第14週開始，瓶內二氧化碳濃度開始降低，第22週可觀察到二氧化碳濃度於暗期上升、光期下降之日變化，培養後第30週二氧化碳濃度於光期結束時降至300 μL．L-1左右。其根莖培養於根莖繁殖培養基，隨蔗糖濃度增加（0%-6%），可促進根莖前端分化成芽體，增加芽體及根部之生長。在抽芽培養基中，提高蔗糖濃度，可增加芽體寬度、根數及鮮重，瓶內二氧化碳及乙烯濃度也隨蔗糖濃度增加而上升，但在6 %蔗糖處理培養第14週時，瓶內乙烯濃度達570 nL．L-1，部分芽體黃化使瓶苗品質下降。 於根莖繁殖培養基添加ACC會促進根莖生長、分支；添加AgNO3則抑制根莖的生長，卻促進芽體分化生長。抽芽培養基添加ACC，明顯抑制地上部，以及後續根的生長；而添加AgNO3的處理有促進芽體生長效果。而於根莖繁殖培養基及抽芽培養基添加50或100 μM AOA對根莖及芽體生長皆有抑制的效果，可能因施用濃度過高而產生毒害。不同培養容器對芽體增殖並無顯著影響，但培養於470 mL三角玻璃瓶者，其芽寬及根徑較370 mL GA-7容器高。

The objective of this study was to investigate the effects of culture medium, ethylene inhibitors, and culture condition on the growth and differentiation of Cymbidium sinense rhizome. In addition, we also investigated the relationship between gas evolvement and the growth and development of rhizome. This study was expected to define the optimal cultural condition and to improve the multiplication, quality, and ex vitro growth of Cymbidium, and could be taken as the base of in vitro physiology research. Sucrose, glucose, fructose and glucose plus fructose were tested in the rhizome propagation medium, the results indicated that the growth of rhizome of Cym. sinense var. albo-jucundissimum and Cym. sinense ‘Chin Hwa Shan’ were not significant affected by the carbohydrate source. Higher concentration of nitrogen was required for the growth and differentiation of rhizome than that of shoot. The optimal nitrogen concentrations for Cym. sinense var. albo-jucundissimum and Cym. sinense ‘Chin Hwa Shan’ rhizome growth were 50.6 mM and 30.0 mM respectively, while the highest fresh weight of shoot and root was achieved with 14.6 mM. Rhizomes of Cym. sinense ‘Rui Bao’ × ‘Guang Hua Die’ were cultured in the rhizome propagation medium and shooting media. Multiplication and growth rates of rhizome and shoot were rapidly increased from Week 4 to Week 12, and CO2 concentration continued to accumulate in the vessel during this period. Carbon dioxide concentration in the vessel started to decrease 14 weeks after the rhizomes were cultured in the shooting medium. After Week 22, CO2 concentration decreased in the light period and increased in the dark period. This change of CO2 concentration showed the characteristics of diurnal rhythm. On the end of light period, CO2 concentration in vitro was declined to 300 μL．L-1 on Week 30. In rhizome propagation medium, increasing sucrose concentration（from 0% to 6%）promoted rhizome tip to differentiate into shoot, and increased shoot and root growth. In shooting medium, raising sucrose concentration increased shoot diameter, root number and total fresh weight, the CO2 and ethylene concentrations in vitro were also increased. Some shoots were chlorosis and ethylene concentration was reached to 570 nL．L-1 with the medium added 6% sucrose. Supplementing ACC in the rhizome propagation medium promoted rhizome growth and branching; however, adding AgNO3 suppressed rhizome growth, but improved shoot differentiation and growth. In shooting medium, adding ACC significantly inhibited shoot and root growth, while AgNO3 increased shoot growth. Adding 50 or 100 μM AOA in both media resulted in suppressing on rhizome and shoot growth, it may be the reason that AOA concentration was too high that leaded to toxicity. On the test of cultural container, although the multiplication of shoot in 470 mL flask and 350 mL GA-7 were not statistically different, the diameter of shoot and root in flask were higher than GA-7.