伟哥能使鲜花延长花期

    小小一粒伟哥不仅能让男性重振雄风，还具有使采摘入瓶的鲜花停止枯萎，水果、蔬菜保鲜期提高1倍的神奇功效。这是以色列和澳大利亚两位科学家昨天公布的最新研究成果。

　　以色列巴依兰大学植物学教授莱谢姆和澳大利亚纽卡斯尔大学食品技术系教授威尔斯共同发现了伟哥对植物的这一特殊保鲜功效。一粒伟哥为50毫克，仅用1毫克稀释后的伟哥喷洒采摘下的满满两瓶鲜花，就可使鲜花的花期延长1倍。莱谢姆教授称，他一直关注伟哥并试图检验伟哥对植物是否有同人一样的特殊功效。植物成熟过程中，内源性一氧化氮减少，乙烯增加。伟哥的使用，延缓cGMP分解，保持了植物体内氧化氮的含量，抑制了导致植物成熟终致腐败的乙烯的产生。他们不仅在鲜花上做了试验，还选择红色的番茄、草莓及绿色的香蕉试验，结果证明，伟哥的确有防止植物老化并保持水果、蔬菜新鲜坚实的作用。

　　对以往称之为废气的氧化氮医学价值的发现和由此开创的生物系统信息传递新理论，使美国3位病理学家夺得了1998年诺贝尔医学奖。他们指出，一氧化氮是一种可以传递信息的气体，可通过细胞薄膜去调节另一细胞的功能。他们对一氧化氮可令血管放松、扩张，帮助血液流通功能的发现导致了美国辉瑞公司伟哥的诞生。

　　莱谢姆教授承认，伟哥被水果和蔬菜吸收后对人和环境有无影响尚不清楚。他说：“我们认为它很可能是无害的，随着摄取后时间的推移，有效成分将被分解。这一过程实际上可能扩张少量肺部血管，反而对肺功能有益。血液通过食物摄取少量的伟哥是否会对男性性功能造成影响正在观察当中，这一保鲜处理过程在被批准使用前还有大量工作要做。”

Viagra makes flowers stand up straight

Judy Siegel-Itzkovich Jerusalem

    Viagra (sildenafil citrate) is good not only for treating male impotence. Israeli and Australian researchers have discovered that small concentrations of the drug dissolved in a vase of water can also double the shelf life of cut flowers, making them stand up straight for as long as a week beyond their natural life span.

    They have already tested Viagra on strawberries, legumes, roses, carnations, broccoli, and other perishables. In this latest research they found that 1 mg of the drug (compared with 50 mg in one pill taken by impotent men) in a solution was enough to prevent two vases of cut flowers from wilting for as much as a week longer than might be expected.

    Professor Yaacov Leshem, a plant researcher at Bar-Ilan University in Ramat Gan, Israel, and Professor Ron Wills of the food technology department of the University of Newcastle, Australia, also patented a safe, cheap process for increasing the shelf life of fruit, vegetables, and cut flowers using nitric oxide. The produce and cut flowers were fumigated with the colourless, odourless gas, an environmental pollutant that in minute quantities acts as the body’s most important signalling molecule.

    The results of the applied research on nitric oxide were first fully reported in late 1998 in Plant Physiology and Biochemistry (1998;36:825-33) and have since been the topic of discussion at international conferences of the food storage and packaging industry. Professor Leshem will present his discovery at the opening plenary session of the September 1999 international conference on fresh cut produce in England.

    An unexpected finding of Professor Leshem’s group is that Viagra has a similar effect on plant ripening as it does on men’s sexual organs. Viagra increases the vase life of flowers by retarding the breakdown of cyclic guanosine monophosphate (cGMP) (the production of which is mediated by nitric oxide).

    Both chemicals could provide the food industry with entirely new, dramatically improved pro-cesses for preserving agricultural produce, Professor Leshem said.

“Nitric oxide is practically free and plentiful, with no identifiable side effects at the very low concentrations we used,” he added. “Right now, Viagra costs much more but does have certain advantages over nitric oxide—for example, it’s easier to use in cut flowers.

“It is now up to industry to develop the engineering methods for large scale, pretreatment of produce based on our discoveries.”

studentBMJ 1999;07 September ISSN 0966-6494