海藻酸钠作为苜蓿种胚和贡柑体胚包裹胶囊的特性

Some Characteristics of Sodium Alginate Made in China in the Encapsulation of Alfalfa Seed Embryos and Somatic Embryos of Citrus

在琼脂培养基中加3％海藻酸钠,可延迟苜蓿种子的萌发,抑制幼苗的生长。海藻酸钠溶液滴入CaCl_2溶液(60mmol),即形成胶囊状颗粒。经这种胶囊包裹的苜蓿种胚,其萌发及幼苗生长不受影响,而贡柑体胚在MT培养上的发芽率,几乎与未包裹的相同,即使在湿润的滤纸层上萌发,其萌发率可达32％。在海藻酸钠溶液中加入1％活性炭,能减少营养成分在胶囊制备过程中的漏出,而且有益于被包裹苜蓿种胚成苗后的发育。用国产海藻酸钠制成的包裹胶囊不发粘。虽然在室温下容易脱水干燥,但在某一含水量下,仍可重新吸水复原。

Alfalfa seed germination and its seedling growth are inhibited by 0.9％ agar medium plus 37％ sodium alginate （chinese product）, but not by the agar medium alone. The addition of the compound in the medium reduced root growth of alfalfa seedlings by 85％ and shoot growth by 74％. This inhibition could be alleviated by adding divalent salts in the medium. CaCl2 was found to completely overcome the inhibition. Autoclaving of sodium alginate caused its viscosity to reduce and conductivity to increase. Capsules were usually formed by dropping 3％ （autoclaved） or 2％ （non-autoclaved） sodium alginate into 60m mol calcium chloride solution. These capsules were not sticky. The capsules were hard enought to be handled on a routine basis without breakage and allowed the radicle of alfalfa embryos to penetrate and germinated as the authentic seeds. The addition of 1％ charcoal into the sodium alginate salution not only decreased the leakage of sucrose from the capsules but also changed the growth ratio of root and shoot of alfalfa seedlings （i.e.improved the shoot development and growth）. After encapsulation the selected somatic embryos of citrus germinated in MT medium as control did, and 23％ of them germinated on the moisture filter paper. The capsules were easy to dry, but it can be rehydrated and its size recovered completely under a key moisture content.