| 2 | Molecular approaches unravel the mechanism of acid soil tolerance in plants显示文摘Acid soil is a worldwide problem to plant production. Acid toxicity is mainly caused by a lack of essential nutrients in the soil and excessive toxic metals in the plant root zone. Of the toxic metals, aluminum(Al) is the most prevalent and most toxic. Plant species have evolved to variable levels of tolerance to aluminum enabling breeding of high Al-tolerant cultivars.Physiological and molecular approaches have revealed some mechanisms of Al toxicity in higher plants. Mechanisms of plant tolerance to Al stress include: 1) exclusion of Al from the root tips, and 2) absorbance, but tolerance of Al in root cells. Organic acid exudation to chelate Al is a feature shared by many higher plants. The future challenge for Al tolerance studies is the identification of novel tolerance mechanisms and the combination of different mechanisms to achieve higher tolerance. Molecular approaches have led to significant progress in explaining mechanisms and detection of genes responsible for Al tolerance.Gene-specific molecular markers offer better options for marker-assisted selection in breeding programs than linked marker strategies. This paper mainly focuses on recent progress in the use of molecular approaches in Al tolerance research. | Miao Bian Meixue Zhou Dongfa Sun Chengdao Li | 2013 | The Crop Journal2013，1，2： | 1 |
| 4 | Structures of ovary and ovarian follicle in flathead lobster,Thenus orientalis (Lund, 1793) (Crustacea: Decapoda: Scyllarida)显示文摘The ovary contains four morphological components: (1) the ovarian wall, (2) the reproductive epithelium, (3) the cellular layer containing oocytes, oogonia (especially for early-developing ovary) and follicle cells, and (4) the extensions of the ovarian wall. The ovarian wall and its extensions consist of blood vessels, sinuses, muscle cells and others. The extensions of the ovarian wall project into among the follicles and insert on the thick basal membrane of each follicle. From inside to outside, the follicles are composed of four parts: (1) the oocyte, (2) the perivitelline space, (3) the follicle cells, and (4) the basal membrane. The surface of the oocyte during vitellogenesis is folded into numerous long microvilli that project into the perivitelline space between the oocyte surface and the bace of the follicle cell layer. In addition, the plasma membrane of the vitellogenic oocyte contains many pinocytotic pits. The perivitelline space is engorged with with more electron- denser material as the development of the follicle. The inclusion of perivitelline space in the mature follicle is named specially as the chorine. The chorion is composed of two region, a thinner exochorion and a thicker endochorion containing electron-dense granular material. The follicle cell layer is composed of a single layer of polygonal follicle cells which exhibit higher synthetic activity. The synthetic product of the follicle cell layer is one scarce for the inclusion of the perivitelline space. The structures of the ovary and ovarian follicle in T. orientalis show that the exogenously biosyn- thetic yolk plays important roles in the vitellogenesis. | Zhu Dongfa, Li Shaojing, Wang Guizhong (1. Department of Oceanography, Xiamen University, Xiamen 361005, China 2. Faculty of Life Science and Biotechnology, Ningbo University, Ningbo 315211, China) | 2001 | Acta Oceanologica Sinica2001，20，2： | 0 |
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