Analysis of Sugars and Fatty Acids during Haustorium Development and Seedling Growth of Coconut

Abstract

Haustorium absorbs energy from the endosperms (liquid and solid) and plays a key role in nutrient mobilization during coconut germination and seedling growth. This study was conducted to shed light on possible interactions between haustorium and endosperms during this process. Germination rates and morphological changes of coconut cultivars Hainan Tall (HT) and Red Dwarf (RD), as well as the profiles of sugars and fatty acids in endosperms and haustorium were also analyzed. Results showed that liquid and solid endosperm inside the coconut exhausts successively, while haustorium occupies the nut gradually. Haustorium had significant positive correlation with seedling, while it had significant negative correlation with liquid and solid endosperms. Sugars in liquid endosperm continuously decreased, whereas in solid endosperm and haustorium accumulated at early stages and decreased later along with the aggressive seedling growth. Fatty acids in solid endosperm shared a very similar trend with sugars. In conclusion, haustorium development and seedling growth mainly depend on the nutrients stored in the liquid endosperm at early stages and then depend on the solid endosperm, in which fatty acids degrade rapidly to sugar so as to provide enough energy. These findings could be applicable in coconut germination and seedling propagation.Core Ideas Relative cool season (25–29°C) is more suitable for coconut germination and local variety (HT) is more adaptable. Development mainly depends on stored nutrients in liquid endosperm at early stages and then on solid endosperm. Fatty acids in solid endosperm degrade rapidly to sugars since liquid endosperm almost exhausted. Conversion of fatty acids to sugars helps provide enough energy for rapidly growing haustorium and seedling.