Flowering and fruiting of the Tropical Intertidal Seagrass H. stipulacea under Controlled ex- situ conditions: Understanding the Effect of Climate change on Sexual reproduction of World’s seagrasses using Ex-situ set ups- A case of Tanzanian coast

Flowers and fruits have not been reported for tropical seagrass Halophila stipulacea along the coast of Tanzania, Indo-Pacific, but after transplanting from Kunduchi intertidal mudflats to experimental cultures, flowers and fruits were observed. Transplanted cuttings from Kunduchi intertidal mudflats were successfully grown in sand-mud substrate in the growth chamber in a 12 hr photoperiod (582 Lux, approximately 20 µmol photons m²s^-1) and an inductive temperature and salinity of 24 - 28 ^oC, 34 - 38 ‰ respectively. Plants began to flower after three months of culturing, while fruits were observed after seven months. A total of 79 flowers and 10 fruits were recorded from January to December; where 54 staminate and 25 pistillate flowers (2:1) were observed throughout the experimental culture. The presence of viable seeds and seedlings demonstrated the successful pollination and sexual reproduction of H. stipulacea in culture. The results of the present investigation suggest that flowering and fruiting in H. stipulacea is related primarily to temperature and salinity; and that differences in flowering and fruiting in responses to temperature or salinity account for the nearly synchronous phenological timing in natural H. stipulacea meadows at different locations along tropical coast of East Africa. This could therefore form the foundation in assessing the impacts of climate change on the world ocean seagrasses; this will therefore allow incorporation of seagrasses into a global science policy for the world’s oceans.