| Quercus is the largest genus in Fagaceae, as one of the most important forest species, there are about110species in China. Quercus contains Subgen. Quercus and Subgen.Cyclobalanopsis. Subgen. Quercus is one of the main species in temperate deciduous broadleared forests. There are23species (include five variation) exist in Shandong province, mainly grow in mid and low altitude mountainous region(Lu in nanshan district and Jiaodong coastal areas). There are few studies about the anatomy of Quercus leaves in China, except one research about the anatomical structure traits of two kinds of Quercus variabilis B1.at different habits.This study, which is about the anatomical structure of the four species, can be considered as a taxonomic character, and can explain some physiological function, and it will be the base of the research which study the leaf response to theenvironment changes.Quercus acutissima Carruth., Quercus variabilis B1.,Quercus mongolica Fish. Ex Ledeb. and Ouercus dentata Thunb. were taken to study the anatomy of leaves and shoots.The mature leaves were collected from Beijiushui (in Laoshan Mountain) at September2011. We divided the crown to three parts:top, middle and the base. At each part we collected three leaves, and get the middle and the base of midvein, and thepetiole. The mature samples were fixed in FAA (70%alcohol). The young stem was collected from the ryondaeHill (in Jinan), and fixed in FAA (50%alcohol).By the method of frozen section, we got the transverse section of the midvein in mature leaves, and transverse section of node in young stems. Compared all the sections of the four Quercus leaves, we found the similarities and differences of the anatomic structure among the four species. The type and distribution of stomata are the same, but the size and the density of stomata are different. They all have palisade tissue in the adaxial side and spongy tissue in the abaxial side, and there are two rows of palisade cells except Quercus acutissima Carruth. The type of the node in the four species is trilacunar. They type of vascular tissue is similar:the vascular bundles connected into a circle, the xylem arranged inside of the circle, the phloem arranged outside, and at the center of the circle there is another vascular bundle group. But the vascular bundle groups have different pattern, some are scattered, and some are combined. To form this vascular type, it went through a complex process in the petiole. Although the structure at the same level of the petiole is different, the whole changing process is similar in the four species. According to the transverse section of the base midvein, we found that the development of the secondary xylem in the four species is different. And it’s not the same in the same species, which were collected from two different places. It indicated that the activity of vascular cambium is related with the species and habitat.By the micro-scanning software AM&DSS2.0and micro-measuring software MIE3.0, we measured the thickness of midvein, vascular bundle groups, the major radius of vessel, vascular bundles, xylem, phloem, phloem fiber, leaf, palisade tissue, and spongy tissue. The data was analyzed by spss13.0. The results indicated that most of the measurement data have significant difference, but the thickness of vascular bundle groups, VBG/MV, leaf thickness and the thickness of first palisade cells are stale in the four species. |
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