Angiosperms need light to synthesize chlorophyll, but lotus (Nelumbo nucifera Gaertn.) embryo was suspected to have the ability to form chlorophyll in the dark because lotus embryo can turn into green under the covera...Angiosperms need light to synthesize chlorophyll, but lotus (Nelumbo nucifera Gaertn.) embryo was suspected to have the ability to form chlorophyll in the dark because lotus embryo can turn into green under the coverage of four layers of integuments (cotyledon, seed coat, pericarp, lotus pod) which were thought impossible for light to pass through. The authors excluded this possibility based on two experimental results: First, enclosing the young lotus pod with aluminium foil, the growth of louts embryo continued, but the chlorophyll formation was seriously inhibited. A lot of protochlorophyllide, chlorophyll precursor, were accumulated, most of which were combined with LPOR (light dependent protochlorophyllide oxidoreductase). Second, DPOR (dark or light-independent protochlorophyllide oxidoreductase) was the enzyme necessary for chlorophyll synthesis in the dark. The genes encoding DPOR were conservative in many species, but no homologues could be found in lotus genome. Taken together, authers' results clearly demonstrated that lotus embryo synthesizes chlorophyll only through the light-dependent pathway.展开更多
The trees in urban landscapes, independent of whether they are in urban forests or stand alone,can improve environment quality, enhance individual and community well-being, provide a wide range ofservices to individua...The trees in urban landscapes, independent of whether they are in urban forests or stand alone,can improve environment quality, enhance individual and community well-being, provide a wide range ofservices to individuals and communities, and produce a more healthful and comfortable environment forthe vast majority of the population. Knowledge of the potential significance of trees in urban landscapesis expanding rapidly as research continues to document the important role that urban forests and trees canplay in improving the quality of urban life. The environmental conditions in urban landscapes are, however,very different from the natural conditions that the tree species are adapted to. This poses big challenges tothe urban forestry in its efforts to create healthy and valuable trees in urban landscapes. Only throughimplementing some important measures we can ensure high survival rate of saplings and well-being andlongevity of urban trees.展开更多
文摘Angiosperms need light to synthesize chlorophyll, but lotus (Nelumbo nucifera Gaertn.) embryo was suspected to have the ability to form chlorophyll in the dark because lotus embryo can turn into green under the coverage of four layers of integuments (cotyledon, seed coat, pericarp, lotus pod) which were thought impossible for light to pass through. The authors excluded this possibility based on two experimental results: First, enclosing the young lotus pod with aluminium foil, the growth of louts embryo continued, but the chlorophyll formation was seriously inhibited. A lot of protochlorophyllide, chlorophyll precursor, were accumulated, most of which were combined with LPOR (light dependent protochlorophyllide oxidoreductase). Second, DPOR (dark or light-independent protochlorophyllide oxidoreductase) was the enzyme necessary for chlorophyll synthesis in the dark. The genes encoding DPOR were conservative in many species, but no homologues could be found in lotus genome. Taken together, authers' results clearly demonstrated that lotus embryo synthesizes chlorophyll only through the light-dependent pathway.
文摘The trees in urban landscapes, independent of whether they are in urban forests or stand alone,can improve environment quality, enhance individual and community well-being, provide a wide range ofservices to individuals and communities, and produce a more healthful and comfortable environment forthe vast majority of the population. Knowledge of the potential significance of trees in urban landscapesis expanding rapidly as research continues to document the important role that urban forests and trees canplay in improving the quality of urban life. The environmental conditions in urban landscapes are, however,very different from the natural conditions that the tree species are adapted to. This poses big challenges tothe urban forestry in its efforts to create healthy and valuable trees in urban landscapes. Only throughimplementing some important measures we can ensure high survival rate of saplings and well-being andlongevity of urban trees.
