The activity of porphobilinogen deaminase was measured in young and senescent or mature leaves of pepper (Capsicum annuum), and poinsettia (Euphorbia pulcherrima). Whereas high activity was found in the crude extracts of the young leaves, almost no activity was found in the extracts of senescent or mature leaves. The decrease in deaminase activity was not due to the presence of an isolatable in...

The objective of this study was to identify the specific weeks and night lengths when poinsettia ( Euphorbia pulcherrima Willd. ex Klotzsch) flowering is most sensitive high temperatures. One experiment conducted in greenhouses under natural daylength (ND) conditions at lat. 34.7°N starting on 4 Sep, a second growth chambers with an initial length (NL) 11 hours 01 minutes that increased by 2 mi...