Using the Kalanchoe daigremontiana Plant to Show the Effects of Photoperiodism on Plantlet Formation

Abstract

he photoperiod refers to the number of hours of light in a 24-hr. period, such as a 10-hr. photoperiod.T Many plants are affected by the photoperiod. For example, the formation of flowers and bulbs often requires a certain photoperiod. A plant that responds only if the photoperiod is less than a certain value is called a short-day plant. A plant that responds only if the photoperiod is more than a certain value is called a long-day plant.The formation of plantlets on the leaves of the houseplant devil's backbone is also controlled by the photoperiod. Devil's backbone is an excellent plant for classroom phototropism experiments that can answer several interesting questions, such as how long must the photoperiod be (termed the critical photoperiod) for plantlets to form. Another question is how many long photoperiods must a plant receive for it to be able to form plantlets. Plantlets form on leaves that develop during long days but not on leaves that develop during short days (Henson and Wareing 1977). This raises the question of why plantlets develop on attached leaves only under long photoperiods, but plantlets form on detached leaves regardless of the photoperiod.In the project described in this article, students determine how many long photoperiods the devil's backbone plant must receive to be able to form plantlets and the critical photoperiod needed for plantlets to form. The students will ~~ ~

Comparative Transcriptome Analysis of Two Kalanchoë Species during Plantlet Formation

“…Additionally, few plants developed a preference for asexual reproduction under certain stress conditions [3]. Moreover, K. daigremontiana plantlet formation is triggered only under long-day conditions [14,26]. With evidence of light-dependent selective preference for asexual or sexual reproduction [3], light or light-associated stress response might be regulating plantlet initiation of K. daigremontiana.…”

“…The developing leaves might be responding to radiation to obtain sufficient light for growth, but also for protection from radiation damage [66,67]. At the same time, the plants might be detecting whether there is sufficient light exposure for plantlet formation as plantlet formation occurs only under long-day conditions [14,26].…”