| The confusion of horticultural varieties is a problem to be solved urgently at present.There are abundant varieties of Jujube Germplasm Resources in China.It is one of the origin and cultivation centers of jujube plants.The confusion of varieties will not only make it difficult to introduce varieties from other places,but also have a great impact on the breeding of hybrid parents and the preservation of resources.The materials used in this study were from the jujube nursery of the Institute of Horticulture,Guangxi Academy of Agricultural Sciences.Through laboratory analysis,the leaf size,ratio of length to width,and density of spine teeth on leaf margin of 34 species of Zizyphus mauritiana were studied quantitatively and qualitatively.At the same time,scanning electron microscopy was used to scan the leaf epidermis micro-morphological characteristics and pollen morphological characteristics,in order to provide more morphological and micro-morphological data for the classification,identification and resource utilization of Zizyphus tomentosa.The main results are as follows.Although leaf shape is often insufficient to provide the main basis for species classification,it is still used as a preliminary step for species identification.Among the 34 species studied,the leaf length ranged from 3.74 cm to 8.71 cm,the shortest was Myanmar round species,the average leaf length was 3.74 cm,the longest was mid-leaf jujube and the average leaf length was 8.71 cm;the leaf width of 34 species ranged from 2.60 cm to 7.17 cm,the shortest was Myanmar round species,the average leaf width was 2.6 cm,the longest was snow honey,and the average leaf width was 7.17 cm;the ratio of leaf length to width of 4 species was 0.6 cm.8-1.92,the smallest is snow honey variation-2,the average ratio of leaf length to width is 0.68,the largest is JD-2,and the average ratio of leaf length to width is 1.92.According to the ratio of leaf length to width,it can be divided into three levels:(a)the ratio of leaf length to width is greater than 1.5,Tianmi,GL-2,Milk Jujube,King Jujube,Variation-3 of Jujube,Pingnan Honey-Spike,Pingnan Honey-Dome,Fusui Changguo,12-2,Gaolang No.1,Late-ripening Milk,Biyun,JD-2,Burma Round Species(b)The ratio of length to width is 1-1.5,Sanmu(No.6),Snow Honey Variation-1,Mid-leaf Honey,Snow Honey,Round Fruit.Leaves,MS-Y-J,Chunmei-J,MS-Y-Y,10-1,12-4,12-3,12-1,SS-Y-J,Honey,MS-Y-B,Crispy honey,Chunmei-S,No.10,Myanmar round species.Another important feature of plant leaves is the leaf margin,which can also be used to classify plants.The extraction of leaf edge features has little damage to plants and is also the simplest and most effective method for classification.According to the density of edge teeth,the tested materials can be classified into two categories,one is less than 5,the other is more than 5.(2)Previous studies have shown that there are interspecific differences in the patterns of extracellular circumferential wall and vertical wall,but the intraspecific pattern is relatively stable,which has important taxonomic value and can provide a basis for the taxonomic identification of some related species of the genus.Scanning electron microscopy(SEM)showed that the outlines and patterns of the periphery wall of epidermal cells in 34 species of Jujube could be divided into the following categories:the periphery wall of epidermal cells was regular polygon,and the periphery wall of epidermal cells was straight;the periphery wall of epidermal cells was regular or irregular polygon,and the periphery wall of epidermal cells was nearly straight or slightly wavy(shallow wave);and the periphery wall of epidermal cells was irregular polygon.The horizontal wall of epidermal cells is irregular polygon,and the vertical wall is deep wave.The types of cuticle on the surface of leaf epidermis cells can be divided into four types:near-smooth,near-smooth and no obvious nodules on the surface of cells;micro-streaks or Micro-Nodules on the surface of cells;obvious ornamentation on the surface of cells;and slight protuberance on the peri-cell wall.The stomatal apparatus were basically distributed in the lower epidermis.According to the characteristics of the outer cover of the stomatal apparatus and whether it has annular uplift or not,the stomatal apparatus can be divided into three categories:circular to elliptical,smooth outer arch cover and no annular uplift around it;according to the endogenous morphological characteristics of the stomatal apparatus,it can be divided into two categories:single layer of the outer arch cover and smooth inner edge;single layer of the outer arch cover and irregular wave shape of the inner edge;single layer of the outer arch cover and near smooth inner edge.Some studies have shown that stomatal density reflects the climate of growth environment.The more arid the climate,the greater the stomatal density of leaves.In this study,it was found that the stomatal density of native varieties in Guangxi and Vietnam was higher,and the climate of Taiwan was slightly wetter than that of Guangxi and Vietnam,indicating that stomatal density was related to the growth environment.(3)Pollen is the product of plant ontogeny,which has strong conservativeness and stability,and is one of the important basis for classification.Pollen polar axis length of 34 species of jujube is 19-34.61 um,of which 12-4 species have the longest polar axis of 34.61 um and the shortest polar axis of mid-leaf jujube is 19 um;the longest polar axis of milk jujube is 16.07-26.83 um,and the shortest is 16.07 um of honey filament;the ratio of polar axis length to equatorial axis length is 0.98-1.7,of which P/E of Pingnan honey-dome is 1.7 and that of Pingnan honey-dome is 1.7 um.The P/E of Suichang fruit was the smallest(0.98),and the length of germination ditch was 15.4-27.9 micron,of which 12-4 had the longest(27.9 micron)and Fusui fruit had the shortest(15.4 micron).Medium-leaf honey jujube,snow-honey variation-1,round leaf,milk honey jujube,king of honey jujube,Pingnan honey-tip,Fusui Changguo,honey,MS-Y-B,Gaolang 1,late-maturing milk,Biyun,Chunmi-S,JD-2,Myanmar round species belong to micro-pollen,Sanmu 6,Tianmi,GL-2,snow-honey,MS-Y-Y,snow-honey variation-2,honey variation-3,Pingnan honey-dome,10-1,12-4,12-3,12-2,12-2,Myanmar round species belong to micro-pollen.-1.SS-Y-J,Crispy Honey and No.10 are medium-sized pollens.The pollen grains of 34 species(varieties)of Jujube are in the form of single grain,and the polar view is nearly triangular,while the red view is nearly circular and oblong. |
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