【作者】 李良希；

【导师】 金研铭；

【作者基本信息】 吉林农业大学 ， 园林植物与观赏园艺， 2011， 硕士

【摘要】 雪柳(Fontanesia fortunei Carr.),属木犀科雪柳属,落叶小乔木或灌木。主要分布于我国东北、华北以及华南地区。目前,雪柳的药理作用以及繁殖等方面已经做了初步的研究。本试验以吉林农业大学校园内的雪柳作为供试材料,利用石蜡切片法、木材切片法、Jeffrey氏离析法、徒手切片法等方法,对雪柳的营养器官进行解剖学研究,并从雪柳的解剖学特性出发,对雪柳的抗旱性加以分析,从而,为雪柳在干旱以及半干旱地区的推广应用提供理论依据。通过试验分析,结果如下：(1)雪柳初生根为星状中柱,初生木质部为二原型,外始式发育；初生韧皮部位于初生木质部之间,呈径向辐射状排列,由筛管、韧皮薄壁细胞构成。(2)雪柳次生根为环孔材,主要由孔纹导管组成,网纹以及环纹导管较少。木射线属异型Ⅱ型,其多列部宽2-3个细胞,木射线密度为34-40枚/mm2,由直立细胞以及横卧细胞构成。轴向木薄壁组织细胞极为丰富,为星散薄壁组织。(3)雪柳初生茎为真中柱,初生木质部内始式发育,髓较发达。(4)雪柳的次生茎属于环孔材,生长轮较为明显。次生木质部中的导管主要为孔纹导管,孔纹导管密度为437枚/mm2。次生茎中管胞较少。木射线属异型Ⅱ型,单列射线较少,多列射线较多,大都宽度为2-3个细胞。木射线在径切面上由直立细胞和横卧细胞构成。筛管、韧皮薄壁组织细胞以及韧皮射线组成雪柳茎部的次生韧皮部,筛管分子的直径约为18.75μm。(5)雪柳叶片为异面叶。上表皮的角质层较厚,没有气孔分布；下表皮细胞较上表皮稍大,气孔分布密集,在20X物镜下,一个视野中气孔数为114个。雪柳叶肉由栅栏组织与海绵组织构成,其栅栏薄壁组织与海绵薄壁组织的比为0.97：1。通过对雪柳营养器官的研究,可以得出：(1)雪柳根部较厚的周皮,多层且排列紧密的木栓层细胞可以有效的保护根,并且在一定程度上保留了根部的水分不过重的向外散失。其根部导管的特征增强了雪柳根在土壤中吸收水分以及运输水分的能力,在受到水分胁迫时,其导管的运输水分的能力会增大,木质部的向心速度会加快,更有利于水分的充分利用,提高了其抗旱胁迫的能力。(2)茎同根一样,均具有较厚的周皮,均为环孔材。Huber认为,环孔材在生长于干旱环境中的植物极为普遍。因此,环孔材可以作为植物适应干旱环境的特征之一。另外,雪柳次生木质部中,其春材的导管数量较秋材多,说明雪柳茎不仅有非常旺盛的输导能力,还能够调节当其处于干旱环境中时的保水以及节水。(3)雪柳叶片上表皮具蜡质,由于蜡质独特的不透水性,能够有效的防止叶片中水分由于蒸腾作用的过分散失,上表皮没有气孔的分布,在一定程度上能够减少雪柳处于干旱环境中时,因蒸腾作用而散失水分,从而表现出其抗旱的特点。雪柳叶片下表皮细胞排列较为紧密,密布气孔,气孔口径较小,且有腺体的分布,这是植物对于干旱胁迫突出的结构特点之一,也是植物对于干旱抵抗的重要机制。雪柳叶肉中,栅栏组织与海绵组织所占比例相当,其栅栏组织中含有一定的叶绿体,说明其栅栏组织不仅仅其道机械支持和保护的作用,在一定程度上也参与了光合作用,促进了叶片中养分的形成。较大而较为疏松的海绵组织则具有相对好的储存水分的能力,从而使其能在较为干旱的条件下顺利进行生长活动。更多还原

【Abstract】 Fontanesia fortunei Carr.is a perennial deciduous shrub of Fontanesia in Oleaceae. In China. it is mainly distributed in the northeastern, northern and southern regions. At present, it has been primarily studied on its pharmacology action and breeding. The experimental material of this study collected from Jilin agricultural university. The structure of the roots, stems and leaves were studied through paraffin section method, unarmed section method, Jeffrey maceration and so on. And analysis th e drought resistance of Fontanesia fortunei from anatomical characteristics.Thus, provide theoretical basis for it used to arid and semi-arid regions.The results are as follows:1.The primary structure of root of Fontanesia fortunei is actinostele. The primary xylem is diarch and exarch. The primary phloem alternate with the primary xylem, and emerge radial arrangement. The sieve tube and phloem parenchyma constitute the primary phloem. The vugs are distributed in cortex.2.The secondary root is ring-porous wood. The secondary xylem is mainly consisted of pitted vessel and little of reticulate vessel and annular vessel. The wood rays are heterogeneous II.The multiseriate rays are 2-3 cells wide. There are 34-40 wood rays in 1mm2.And it consist of upright and procumbent ray cell. Ther wood parenchyma is abundant. As well as, it belongs to diffuse parenchyma.3.The primary shoot is eustele. It has endarch primary xylem and developed pith.4.The secondary stem is ring-porous wood and the the growth ring is very clear. The secondary xylem is mainly consisted of pitted vessel. There are 437 pitted vessels in 1mm2.There is little of tracheid in secondary stem. The wood rays are heterogeneousⅡ. There are little of uniseriate ray and lots of multiseriate ray. The multiseriate rays are 2-3 cells wide. The wood rays consist of upright and procumbent ray cell. The secondary phloem is mainly consisted of sieve tube, phloem parenchyma and phloem ray.The diameter of sieve elements is 18.75μm.There are druse in bast parenchyma cells.5.The leaf is dorsi-ventral type. The cuticle of epicuticle is thicker and there is no stomata on the epicuticle. The lower epidermis cells are bigger than epicuticle. The stoma distribute widely on lower epidermis. There is some glandular hairs on the lower epidermis. The number of the stoma in 20×view is 114. The mesophyll consists of palisade tissue and spongy tissue. The ratio of palisade tissue and spongy tissue is 0.97:1.There are druse in the parenchyma of mesophyll, petiole and leaf vein.We can get results through the nutritive organ research of Fontanesia fortunei:1.The periderm of root is very thick. The multilayer cork layer cells arrange very close, so it can conserve the water of root. The characteristic of roots increase the ability of root sucking and transport water in soil. When the water is insufficiency, the ability of transport water will increase, the entad speed of xylem will accelerate. So it is more benefit to the availability of the water. And the drought-resisting capability will raise.2.The stem is similarity to the root. The periderm is very thick. The stem and root are ring-porous wood. Huber considered that the ring-porous wood is common in the plants which grow in drought. So it can be used as the characteristic of the plants fit the drought. Moreover, the number of vessel in spring wood is bigger than autumn wood,this result explained that the ability of dredge water of stem is very vigorous, and adjust the water use ratio when it is in drought environment.3.The epicuticle of leaf have waxiness. The waxiness can reduce the water lost in leaf because the waxiness is waterproof. There is no stoma on epicuticle, so it can reduce the water lost to a certain extent.The cells of lower epidermis is very close. There are lots of small stoma on it. There are some glandular hairs on the lower epidermis. This is one of the plant’s drought resistance characteristic and the mechanism of the plants resist the drought environment.The mesophyll of Fontanesia fortunei, the thickness of palisade tissue and spongy tissue is nearly the same. There are some chloroplast in the palisade tissue, it can explain that the palisade tissue participate in photosynthesis. The loose and big spongy tissue has better ability of storing water, thereby the plants can live in drought environment.更多还原