植物化学通讯研究进展

 生物的信息传递是生命科学中引人入胜的研究领域之一，生物种间种内和个体内都存在着物理和化学等各种信息交流方式。植物种间种内是否通过物理信号进行通讯交流还是一个未知数，但邻近的同种或异种植物通过化学物质为媒介的通讯关系确是客观存在的。最近，愈来愈多的研究证明：许多陆生植物种可以合成并释放特定的次生物质，这些次生物质可以通过空气和土壤两种载体进行信息传递，尤其是在植物受到侵袭和寄生条件下。茉莉酮酸甲酯、水杨酸甲酯和乙烯等挥发性次生物质被确证为以空气为媒介进行植物种间和种内通讯的化学信号分子。植物根分泌的黄酮和氢醌等分子也可以经土壤媒介传递信息。由于在自然条件下植物根系分泌物的收集和活性信号分子的俘获及鉴定技术还未能突破，这增加了以土壤为媒介的植物种间和种内化学通讯关系研究的难度。但不论如何，植物的化学通讯是植物种间和种内交流的主要方式，植物间的化学通讯关系的研究还处于突破的前夜，这方面的任一研究成果都会引起世界性的关注。因此，破译植物种间和种内化学通讯密码具有重要的学术价值。

ADVANCE IN THE RESEARCH ON CHEMICAL COMMUNICATION BETWEEN PLANTS

Bio-signalling transduction is one of the exciting fields in life sciences. There are variously physical and/or chemical modes for communication among organisms and their cells and organs. Actually, the environment is replete with chemicals, many of which have become part of a system of chemical communication. Chemical signals may operate on any of five levels of increasing complexity that correspond to cells, organs, organisms, groups and communities. It is unclear whether there is physically intraspecific or interspecific signals between plants. However, it was confirmed that plant can interpret and respond to secondary metabolites released by neighboring plants. Interplant chemical communication can occur among one species and another species of plant through air or soil media. Plant might warn each other about an imminent attack. The chemical recognition might occur between host and parasitic or associated plants. Methyl jasmonate(MJ) is a volatile chemical messenger that diffuses through the air from wounded plants, is potent in very small quantities, and starts a general signal cascade for increased production of defense chemicals in a wide range of plant families. Precursor of MJ is jamonic acid (JA), which occur in plant tissue and is also intercellular signal molecule in the systemic resistance of plants against herbivory. When interplant communication occurred through airborne signal, JA was converted to MJ, which is more volatile at room temperature, potentially allowing it to affect both remote parts of the releaser plant as well as nearly plants. More recently, other volatile chemicals implicated in plant to plant information transfer also were revealed. Methyl salicylate, ethylene and some α,β-unsaturated carbonyls have been reported for airborne plant to plant signals. Interplant chemical signals can also mediate through soil. The root-soil interface is a site where many interactions occur between plants and their environment. Some plants exuded chemical messengers by root tissue. A few chemicals from root exudates of host plant are germination stimulants and may be recognized by associated and parasitic plant. The seed of parasitic witchweed may be rapidly germinated by hydroquinone and sesquiterpene that respectively released from gramineous crops and cotton root tissues. Apigenin and cyclic xanthmine from legume root exudates were possible chemical messages through the root-soil interface. Nevertheless, it was difficult to capture and identify active chemicals from root tissues. As a result, interpretation of chemical signal on the root-soil interface has few progresses. In a word, the chemical messenger plays an important role in plant communication. Interpretation of the chemical signals among plants will be important scientific significance.