对水培条件下单瓣、双瓣和重瓣茉莉(Jasminum sambac Aiton)插穗的生根能力及根尖解剖结构差异进行了观察和比较;在此基础上,分析了茉莉各生根性状及根尖解剖结构特征间的相关性。结果表明:3 种瓣型茉莉插穗的生根率均达到100%,但单株生根数和平均根长均有显著差异(P<0. 05);其中,双瓣茉莉的单株生根数和平均根长均最大,重瓣茉莉的这2 个生根指标均最小。解剖结构观察结果表明:3 种瓣型茉莉插穗水培根尖具有细胞质染色较浅、根冠细胞壁较薄和细胞内含物较少等特征;根尖成熟区和伸长区都出现不规则的气腔,类似于水生植物根系通气组织的结构;但不同瓣型茉莉根冠和气腔性状有一定差异。单瓣、双瓣和重瓣茉莉根冠长度分别为550、503和480 μm,根冠长/ 宽比分别为1. 52、1. 34 和1. 21,三者间均有显著差异(P<0. 05);重瓣茉莉的根冠宽度最大(395μm)且与双瓣和单瓣茉莉差异显著(P<0. 05)。单瓣茉莉每根尖气腔数及气腔长度和宽度均最小,与双瓣和重瓣茉莉差异显著(P<0. 05);而重瓣茉莉气腔宽度最大、双瓣茉莉气腔长度最大。相关性分析结果表明:水培条件下茉莉插穗的生根能力与根冠和气腔各性状指标的相关性均不显著(P>0. 05)。总体上看,水培条件下双瓣茉莉插穗生根能力最强,根尖内气腔数量多且通气组织状结构最为发达,其抗逆性较强与此有关。研究结果揭示:不同瓣型茉莉水培生根能力及根尖解剖结构变化与其对水生环境的适应性有一定关系。

Differences in rooting ability and root-tip anatomical structure of cuttings of single-petal, double-petal and multi-petal types of Jasminum sambac Aiton were observed and compared under hydroponic culture. And on these bases, the correlation among rooting character and root-tip anatomical structure characteristics was analyzed. Results show that the rooting rate of cuttings of three petal types all reaches to 100% but there are significant difference (P<0. 05) in root number per plant and average root length, in which, both root number per plant and average root length of cutting of double-petal type are the maximum and those of multi-petal type are the minimum. The observation result of anatomical structure shows that hydroponic root tips of cuttings of three petal types possess some characteristics of cytoplasm strain lightening, cell wall in root cap thinning and cell content lessening, and there are irregular air chambers in elongation and maturation zones of root tip, which is similar to aerenchyma structure of aquatic plant. But there are a certain differences in characters of root cap and air chamber among different petal types of J. sambac. Root-cap length of single-petal, double-petal and multi-petal types is 550, 503 and 480 μm and ratio of length to width of root cap is 1. 52, 1. 34 and 1. 21, respectively, with the significant difference (P <0. 05). And root-cap width of multi-petal type is the highest (395 μm) with the significant difference (P <0. 05) to double-petal and single-petal types. Number of air chamber per root tip, length and width of air chamber of single-petal type is the minimumwith the significant difference (P <0. 05) to double-petal and multi-petal types. While width of air chamber of multi-petal type is the maximum, length of air chamber of double-petal type is the maximum.Correlation analysis result shows that rooting ability of J. sambac cuttings possesses unsignificant correlation (P >0. 05) with all characters of root cap and air chamber. Generally, rooting ability of cuttings of double-petal type of J. sambac is the strongest with more air chamber and more developed aerenchyma structure in root tip under hydroponic culture, so it is related to stronger resistance to stress environment. It is suggested that changes in hydroponic rooting ability and root-tip anatomical structure of different petal types of J. sambac are related to their adaptability to aquatic environment.