The maize and neorgelia cawlinae meyendor ffii were treated with uv - b radiation with the intensities of 0uw . cm - 2 ( ck ) , 10uw . cm - 2 ( r1 ) and 15uw . cm - 2 ( r2 ) , the duration of uv - b treatment were ten hours per day ( from am8 : 00 to pm18 : 00 ) . the effect of uv - b radiation on the photosynthesis was studied , and the results showed as follows : ( l ) the effects of uv - b radiation on photosynthesis of maize and neorgelia cawlinae meyendor ffii the results of the experiment show that the photosynthesis of maize seedlings was restrained because of the decrease of chlorophyll contents activity of hill reaction stamotal conductance activity of pepcase and atp content caused by increased uv - b radiation , and it was more restrained under higher uv - b radiation . though the activities of rubpcase and pepcase were decreased , the chlorophyll contents activity of hill reaction stamotal conductance of mature maize were not affected , therefore the photosynthesis of grown - up plant was not affected Cm ~ ( - 2 ) ( r2组)的uv - b辐射，每天处理10小时( 8 ： 00 ? 18 ： 00 ) ，直至玉米成熟，以自然光照为对照( ck组) ，对增强uv - b辐射条件下玉米和红彩凤梨光合作用的响应作了深入的研究和探讨，结果如下： ( 1 ) uv - b辐射对玉米和红彩凤梨光合作用的影响研究结果表明，因增强uv - b辐射降低了玉米幼苗叶片的叶绿素含量、 hill反应活力、气孔导度、 pepcase活性和atp含量，从而影响了玉米幼苗的光合作用，使其光合速率下降，且随uv - b辐射强度的增加其影响程度加大；而玉米成株在增强uv - b辐射环境下其叶绿素含量、 hill反应活力、气孔导度等未受影响，虽然其rubpcase活性和pepcase活性有所下降，但总体上其光合作用受到的影响不大。
2.
T . media cv . hicksii seedling " s total leaf area , specific leaf area , biomass , blade ' s thickness , apparent quantum efficiency ( aqy ) and the activity of hill reaction in one - layer shading are biggest . it shows that the ability using weak light is the strongest , which is favour of the accumulation of assimilating outgrown , and that it grows suitably at the place in shading 一层遮荫下生长的植株叶面积、比叶面积、叶片厚度、生物量、叶绿素含量、表观量子效率及hill反应活力最大，说明它利用弱光的能力最强，有利于同化产物的积累，适宜于在遮荫处生长。
