Pollen Bud Formation and its Role in Ophiorrhiza spp.

The anther in Ophiorrhiza is dithecous and tetralocular, itsdevelopment being of the dicotyledonous type. The anther wallcomprises epidermis, endothecium, middle layer and secretorytapetum. The pollen grains are tricolpate and triporate. Themicrospore nucleus undergoes division to form a vegetative nucleusand a generative nucleus and protrusions (pollen buds) are formedfrom the germ pores after the first division of the microsporenucleus. The vegetative nucleus moves into one of these budsor first breaks into a number of irregularly sized nuclear particleswhich enter into one, two or into all three buds, where theydegenerate. Then the pollen buds are separated and the generativenucleus divides inside the pollen tube to form two sperms. Ophiorrhiza harrisiana, Ophiorrhiza hirsutula, microsporogenesis, pollen buds, vegetative nucleus     

Non‐specific phospholipase C5 and diacylglycerol promote lateral root development under mild salt stress in Arabidopsis

Developing a robust root system is crucial to plant survival and competition for soil resources. Here we report that the non‐specific phospholipase C5 (NPC5) and its derived lipid mediator diacylglycerol (DAG) mediate lateral root (LR) development during salt stress in Arabidopsis thaliana. T‐DNA knockout mutant npc5‐1 produced few to no LR under mild NaCl stress, whereas overexpression of NPC5 increased LR number. Roots of npc5‐1 contained a lower level of DAG than wild type, whereas NPC5 overexpressor exhibited an increase in DAG level. Application of DAG, but not phosphatidic acid, fully restored LR growth of npc5‐1 to that of wild type under NaCl stress. NPC5 expression was significantly induced in Arabidopsis seedlings treated with NaCl. Npc5‐1 was less responsive to auxin‐mediated root growth than the wild type. These results indicate that NPC5 mediates LR development in response to salt stress and suggest that DAG functions as a lipid mediator in the stress signalling.