Explant, medium and vessel aeration affect the incidence of hyperhydricity and recovery of normal plantlets in triploid watermelon
Explant, medium and vessel aeration affect the incidence of hyperhydricity and recovery of normal plantlets in triploid watermelon
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DOI：
10.1080/14620316.2000.11511194
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发表时间：
2000-01
期刊：
影响因子：
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通讯作者：
P. Thomas;J. B. Mythili;B. Stumman;K. Shivashankar
中科院分区：
文献类型：
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作者：
P. Thomas;J. B. Mythili;B. Stumman;K. Shivashankar
摘要 在三倍体西瓜 (Citrullus lanatus (Thunb.) Matsum. & Nakai) `Arka Manik' 微繁殖过程中，水分过多或玻璃化是一个常见问题，这受到 BA、外植体、培养基和容器通气水平的影响。高 BA (5±10 mM) 会产生多个芽，并导致高含水量的发生率和强度，而使用低 BA (1 mM) 则有利于单芽生长，且高含水量相对较低。高水培养物通常在传代培养时表现出不同程度的玻璃状或根本无法生长。 1 mM BA 培养基上的低度高水芽的芽尖和上部节段在继代培养中通常显示出正常生长，而下部节往往呈现玻璃状生长。因此，延迟继代培养会导致水分过多。 Rugini olive (RO) 基础培养基比 MS 培养基表现出更好的培养物生长和更少的超水性。使用更多的胶凝剂（植物凝胶 2.5 g vs. 3 g l1 或琼脂 8 vs. 10 g l21），用琼脂 (10 g l1) 替代 phytagel (3 g l1)，在培养基中加入渗透剂甘露醇和山梨醇（各 500 mg l1），或使用直径为 1.25 或 2.5 cm 的盖子，并用棉质铺位覆盖，以改善容器通气或硝酸纤维素过滤器（0.2毫米孔径）单独有助于在一定程度上减少水分过多。通气的规定相对优于其他方法，但更多的通气（2.5 厘米直径）会导致更快的培养基脱水和生长限制。通过采用低 BA (1 mM)、渗透剂、琼脂胶凝和使用 RO 或 MS 基础培养基的容器通气（直径 1.25 厘米棉铺）的组合，可以有效地检查超水性/玻璃状，并获得令人满意的生长。通过采用这种方法，结合更好的通气（1.25 厘米过滤器或 2.5 厘米铺位）以及选择性使用茎尖和上部节段，可以挽救或恢复高水分储备培养物以实现正常生长。解决超水问题后，尝试使用 5-10 mM BA 进行多芽诱导来提高繁殖率，结果表明，在低 BA (1 mM) 存在的情况下，使用芽尖和节插条进行单芽生长优于前者，可提供更好的净繁殖和正常植物。
Summary Hyperhydricity or glassiness was a frequent problem during the micropropagation of triploid watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai) `Arka Manik' and this was influenced by level of BA, explant, medium and vessel aeration. High BA (5±10 mM) gave multiple shoots and led to high incidence and intensity of hyperhydricity while the use of low BA (1 mM) facilitated single-shoot growth with relatively low hyperhydricity. Hyperhydric cultures generally exhibited varying degrees of glassiness on subculturing or failed to grow at all. Shoot tip and upper nodal segments from lowly hyperhydric shoots on 1 mM BA medium often showed normal growth on subculturing while lower nodes tended to give glassy growth. Delaying subculturing thus contributed to hyperhydricity. Rugini olive (RO) basal medium showed better culture growth and less hyperhydricity than MS medium. Use of more gelling agent (phytagel 2.5 g vs. 3 g l1 or agar 8 vs. 10 g l21), substitution of agar (10 g l1) for phytagel (3 g l1), incorporation of osmotic agents mannitol and sorbitol (500 mg l1 each) in the medium or improving vessel aeration using caps with a 1.25 or 2.5 cm diameter opening covered with cotton bunk or cellulose nitrate filter (0.2 mm pore size) individually helped in reducing hyperhydricity to some extent. Provision for aeration was relatively superior to other approaches but more aeration (2.5 cm diameter) led to faster medium dehydration and growth limitation. Hyperhydricity/glassiness could be checked effectively with satisfactory growth by adopting a combination of low BA (1 mM), osmotic agents, agar gelling and vessel aeration (1.25 cm diameter cotton bunks) using RO or MS basal medium. Hyperhydric stock cultures could be salvaged or reverted to give normal growth by employing this approach coupled with better aeration (1.25 cm filter or 2.5 cm bunks) and selective use of shoot tip and upper nodal segments. Attempts to improve the propagation rate through multiple shoot induction using 5–10 mM BA after solving the hyperhydricity problem indicated that single-shoot growth using shoot tip and nodal cuttings in the presence of low BA (1 mM) was superior to the former, giving better net multiplication and normal plants.