engleski

Green spathe of peace lily (Spathiphyllum wallisii): an assimilate source for developing fruit

Peace lily (Spathiphyllum wallisii Regel) is a herbaceous, commercially important ornamental plant characterized by greening of its originally white spathe during a post-anthesis period and fruit development. It is a useful model plant for gaining insight into source-sink relationship. To clarify what is the triggering signal for spathe greening and its potential physiological role, the greening process has been examined in fertilized vs unfertilized and decapitated (with spadix removed) plants. Results showed that spathe of fertilized plants is viable for a longer period of time and greening process is more intensive in comparison with decapitated or unfertilized plants. Greening process comprised chloroplast differentiation as well as chlorophyll accumulation, and resulted in the photosynthetically active organs. Photosynthesis performance index (PIABS) of spathe in fertilized flowers was significantly higher than that in unfertilized and decapitated plants, indicating its better overall photosynthetic performance. Spathe removal during fruit development revealed approximately 30% smaller fruits in comparison with intact ones, implicating that green spathe contribute significantly as assimilate source for developing fruits. Cytokinin analysis showed that t-Z-type cytokinins were the most abundant in the spadix (t-Z and t-ZR) and the greening spathe (t-ZR), while overall cytokinin pool was significantly lower in the spathe of the decapitated plants. Exogenous treatment of spathe in decapitated plants with t-Z enhanced the intensity of greening. We may conclude that spathe greening in peace lily is genetically programmed process that may be mediated by fructification and, in part, by cytokinins originated in the developing fruit which was confirmed herein for the first time.

Cytokinin ; Fruit ; Non-foliar photosynthesis ; Peace lily ; Source-sink communication ; Spathe greening

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