大苞鞘石斛原球茎超低温保存中生理生化变化1）

以继代培养60 d的大苞鞘石斛原球茎（矱＝2～3 mm）为材料,对比研究低温高渗（HT＋CA）和室温高渗（HT-CA）2种预处理方法对原球茎玻璃化法超低温保存冷冻前含水量以及预处理、脱水和解冻3个关键步骤中相对电导率、丙二醛质量摩尔浓度、可溶性糖和可溶性蛋白质量分数的影响,并结合显微结构观测和组织化学分析揭示高渗预处理影响超低温保存后原球茎相对存活率的生理生化基础。结果表明：在冷冻前,干样含水量显著降低,当干样含水量下降为1．06 g? g-1时,冻后相对存活率达最大值,为46．6％;预处理和脱水显著地提高了相对电导率;脱水和解冻使丙二醛质量摩尔浓度显著升高;可溶性糖和可溶性蛋白质量分数呈显著上升后明显下降的单峰变化曲线。多元相关分析表明,丙二醛质量摩尔浓度与相对存活率之间呈极显著负相关（相关系数为-0．992）,膜脂过氧化作用是影响大苞鞘石斛原球茎冻后成活的关键因素之一。显微结构观察到细胞膜在预处理和脱水过程中受到明显破坏;组织化学分析显示淀粉粒和蛋白质的分布多集中在未受损伤的顶端分生组织中,分布变化呈先增多后减少的趋势,这与生理生化分析的结果是一致的。     

High frequency multiplication of Phalaenopsis gigantea using trimmed bases protocorms technique

This study was conducted to determine the effects of coconut water (CW) and activated charcoal (AC) on multiplication of Phalaenopsis gigantea protocorms. The protocorms used for this study were obtained by germinating seeds in vitro. Protocorms with trimmed and untrimmed bases were cultured on XER basal medium containing 0, 10, 15 or 20% (v/v) CW; and 0, 1, 2 or 2.5 g AC l⁻¹. Trimmed protocorms exhibited the highest percentage of proliferation on a medium containing 15% (v/v) CW and 2.5 g AC l⁻¹ (56.82 ± 38.86%) with an average of 4.24 ± 2.89 protocorms formed per protocorm. Untrimmed protocorms cultured on a medium containing 20% (v/v) CW without AC produced the highest percentage of new protocorms (6.93 ± 6.28%) with an average of 0.72 ± 0.57 per protocorm. When CW was added to a medium singly, 10% (v/v) CW induced a higher degree of proliferation on trimmed protocorms (5.68 ± 10.14%) with an average 0.50 ± 0.84 new protocorms per protocorm. Untrimmed protocorms proliferate to a much lower extent (2.57 ± 2.74%) with an average of 0.72 ± 0.57 protocorms per protocorm when cultured on a similar medium. A high concentration of CW enhanced proliferation on untrimmed protocorms, but increased mortality of trimmed protocorms. The addition of CW with AC to media increased protocorm proliferation and survival of both trimmed and untrimmed protocorms. When cultured on all media, trimmed protocorms produced a higher number of new protocorms (an average 0.5–7.0) as compared to untrimmed protocorms (0.3–1.9). Comparative studies showed that trimmed protocorms produced up to 10 times more new protocorms than untrimmed ones. Altogether this study showed that trimmed protocorms cultured on a medium containing CW and AC can be used for high-frequency multiplication of P. gigantea seedlings.     

铁皮石斛种子、原球茎和类原球茎体的超低温保存研究

对珍稀濒危植物铁皮石斛的种子、原球茎和类原球茎体进行了液氮超低温保存研究。把４个月龄的种子脱水至含水量为１２％～１９％,能获得较高的冻后存活率（９５％）和较快的恢复生长速率。种子在０．５ｍｏｌ／Ｌ脱落酸培养基上萌发３周所形成的原球茎,用玻璃化保护剂ＰＶＳ２处理１５ｍｉｎ,其冻后存活率可达８８％。将生长旺盛的暗培养类原球茎体的含水量在６～７ｄ内干燥至３０％±２％,其冻后存活率可达４８％～８０％。     

不同植物生长调节剂对白及种子萌发及幼苗生长的影响

[目的]研究不同植物生长调节剂对白及种子萌发及幼苗生长的影响。[方法]利用组织培养的方法,采用不同植物生长调节剂处理,比较白及叶长、叶宽、株高及原球茎大小的差异。[结果]不同植物生长调节剂处理间,白及幼苗的生长表现出显著差异。2,4-D均能诱导种子产生愈伤组织;6-BA、KT对白及幼苗叶长及原球茎的生长有抑制作用,KT对其叶宽、株高有抑制作用;NAA、IBA对白及幼苗叶长及叶宽的生长有促进作用,但NAA较IBA强,NAA还对其株高有促进作用。[结论]不同植物生长调节剂的单因素处理中,2,4-D诱导白及种子产生愈伤组织的最佳浓度为1.0 mg/L,诱导率为100%,其余成苗的植物生长调节剂处理中,NAA较IBA、6-BA、KT较好,0.5、1.0 mg/L NAA对幼苗的生长效果均较好;不同植物生长调节剂组合处理中,仅2,4-D对白及种子愈伤组织的诱导有显著影响。