Most drug forms have historically been cultivated in areas south of the north-temperate zone, sometimes close to the equator, where they may be photoperiodically
adapted to near-12-h days and an associated long season.
This photoperiodically mediated change in activity provides an interesting result.
1980; Skilbrei, 1991), a mechanism that has long been known to be photoperiodically induced (Villarreal et al.
Zhang and Du (1999) found that photoperiodically sensitive cultivars display shortened vegetative stages (Ve to Vt) (Fehr and Caviness, 1977), as well as shortened reproductive stages when grown under 8- vs.
1996a) as the most photoperiodically responsive, providing the greatest delay of flowering.
The study by Loper and Lapioli (1971) on the physiology of flower volatile emanation indicated that this is an active metabolic process with large fluctuations within short times (hours) and that it is a photoperiodically
1997) clearly identified photoperiodically sensitive and insensitive phases during the PFP, by plotting days to flowering against days to transfer.
Photoperiodically sensitive and insensitive phases of preflowering development in rice.
It is noteworth that, in addition to aestivating, adults overwinter in a photoperiodically regulated diapause, which also involves a genetically variable switch mechanism (Tauber and Tauber, 1982).
In contrast, C downesi is characterized by a photoperiodically mediated univoltine life cycle throughout the region; reproduction occurs only when individuals experience a sequence of short daylengths followed by long daylengths (Tauber and Tauber, 1976, 1986).
Duration of Photoperiodically Sensitive and Insensitive Phases
Photoperiodically sensitive interval in time to flower of soybean.