Date Palm Germination: Mysteries Unlocked
Xiao et al. investigate date palm germination. Plant Cell (2019) https://doi.org/10.1105/tpc.19.00008
By Ting Ting Xiao and Ikram Blilou
Background: Desert plants have evolved different strategies to survive desert climate. Developmental mechanisms underlying these adaptive strategies remain poorly described. Date palm (Phoenix dactylifera), is one of the few desert fruit plants that are widely cultivated. It is an important source of food, fuel, shelter and fiber. Date palm can tolerate drought, heat, and high levels of soil salinity. A specialized root system is thus required for date palm to optimally absorb water and nutrient in addition to soil anchorage.
Question: From seed to plant, what are the developmental strategies used by date palm to grow in the hostile desert environment?
Findings: We found that unlike most of plant species where organs develop immediately after germination. In date palm, this process is unique and it is termed remote germination. It starts with a root like structure that emerges from the seed and forms a rapidly growing multi-layered tuber-like structure (Cotyledonary petiole). During this early developmental stage, the embryo remains quiescent. This developmental pause is one of the strategies that date palm employs to protect the embryo during early development and it is reminiscent to diapause in animals. We reveal that in date palm organs remain protected within the cotyledonary petiole that extends toward the soil to bury the plant body. This unique strategy provides an ecological advantage where the young seedling is placed below ground to escape the dry soil surface and high temperatures characteristic of the desert environment. In addition, date palm has a well-designed and highly specialized root system. This great hydraulic system allows date palm to optimally manage water and nutrient uptakes.
Next steps: Identify mechanisms conferring these adaptation strategies and transfer the knowledge to create crops with optimal roots that can grow in desert lands.
Ting Ting Xiao, Alejandro Aragón Raygoza, Juan Caballero Pérez, Gwendolyn Kirschner, Yanming Deng, Brian Atkinson, Craig Sturrock, Vinicius Lube, Jian You Wang, Gilles Lubineau, Salim Al-Babili, Alfredo Cruz Ramírez, Malcolm Bennett, and Ikram Blilou (2019). Emergent Protective Organogenesis in Date Palms: A Morpho-Devo-Dynamic Adaptive Strategy during Early Development. Plant Cell https://doi.org/10.1105/tpc.19.00008
Key words: Roots, Desert, Date palm, Remote germination