Gegensätzliche Geschlechtsausprägung von Blütenstandsanlagen der Langtagpflanze Lemna gibba und der Kurztagpflanze Lemna paucicostata in vitro

Abstract

Inflorescence primordia of two species of the genus Lemna develop on synthetic agar media in vitro. On medium consisting of agar, salts of the PIRSON-SEIDEL-solution, sucrose, kinetin, gibberellic acid, indoleacetic acid, some vitamins, nucleotides and casein hydrolysate the explants of the long-day plant Lemna gibba and of the short-day plant Lemna paucicostata develop in a similar manner. Young, fully meristematic primordia (stage 2) show only little or no growth response, whereas primordia of both species with a pistil length of ≥ 0.08 mm (stage 3) always undergo some growth. With stage 4 full development of all flower organs occurs, if medium composition is adequate. With stage 5 not only mature flowers develop, but also fructification and development of ovules to unripe seeds occur. On a more simple medium containing 2 % sucrose and 1 mg/1 kinetin as the sole organic additions, better development occurs especially in the younger stages. On this medium, however, the relative development of stamens and pistils is altered. In Lemna gibba pistil development is enhanced, which leads to feminisation. In Lemna paucicostata growth of stamens is enhanced, which leads to masculinisation of the explants. This different developmental behaviour of the two photoperiodic reaction types presumably is due to a different endogenous hormone production in the meristems of both species.