Coconut (Cocos nucifera L.) is an important perennial crop adapted to a wide range of habitats. Although global coconut demand has increased sharply over the past few years, its production has been decreasing due to palm senility, as well as abiotic and biotic stresses. In fact, replanting efforts are impeded due to the lack of good quality seedlings. In vitro technologies have a great potential; however, their applications may take time to reach a commercial level. Therefore, traditional seed propagation is still critical to help meet the rising demand and its practice needs to be improved. To achieve an improved propagation via seeds, it is important to understand coconut fruit biology and its related issues. This review aims to provide a comprehensive summary of the existing knowledge on coconut fruit morpho-anatomy, germination biology, seed dispersal, distribution, fruit longevity and storage. This will help to identify gaps where future research efforts should be directed to improve traditional seed propagation.

Coconut [Cocos nucifera L.] is often called “the tree of life” because of its many uses in the food, beverage, medicinal, and cosmetic industries. Currently, more than 50% of the palms grown throughout the world are senile and need to be replanted immediately to ensure production levels meet the present and increasing demand for coconut products. Mass replanting will not be possible using traditional propagation methods from seed. Recent studies have indicated that in vitro cloning via somatic embryogenesis is the most promising alternative for the large-scale production of new coconut palms. This paper provides a review on the status and prospects for the application of somatic embryogenesis to mass clonal propagation of coconut.

Using seeds to restore natural ecosystems has a greater chance of success if the seeds used are ready to germinate given appropriate environmental conditions. For Australian native Poaceae species, seed quality and dormancy can impose constraints on restoration success. In this study, germination biology of three Australian native Poaceae species, such as Cymbopogon refractus, Capillipedium spicigerum and Bothriochloa bladhii, was investigated. The seeds were exposed to different germination-enhancing chemicals (GECs, namely smoke water (SW), potassium nitrate (KNO3) or a combination (SW + KNO3)) and treated with three different seed enhancement technologies (SETs, namely seed priming, seed coating or seed cookies) then sown into two contrasting soil types (sodosol or black vertisol). Laboratory germination percentages achieved were <50% for all species, limited by dormant seeds. Incorporating GECs together with seed priming or seed coating treatment significantly increased seedling emergence rates and promoted earlier emergence as compared to the untreated control. For C. refractus and C. spicigerum, priming and/or coating with KNO3 + SW had the highest cumulative emergence. For B. bladhii, total seedling emergence was the highest (36% in both soils) for primed seeds with KNO3. Seedling emergence from seed cookies was low in all three species (<15%). Generally, soil type did not influence emergence rates for either GEC or SET. Understanding the environmental requirements needed for seed germination, together with an appropriate pre-treatment before sowing, can speed up seedling emergence and increase total emergence when using native Poaceae species for seed-based restoration.

Understanding how seed functional traits interact with environmental factors to determine seedling recruitment is critical to assess the impact of climate change on ecosystem restoration. This study focused on the effects of environmental factors on the mother plant during early plant life history stages and during seed development. Desmodium brachypodum A. Gray (large tick trefoil, Fabaceae) was used as a model species. Firstly, this study analyzed seed germination traits in response to temperature and moisture stress. Secondly, it investigated how seed burial depth interacts with temperature and soil moisture to influence seedling emergence traits. Finally, it determined if contrasting levels of post-anthesis soil moisture could result in changes in D. brachypodum reproductive biology and seed and seedling functional traits. The results showed that elevated temperature and moisture stress interacted to significantly reduce the seed germination and seedling emergence (each by >50%), while the seed burial improved the seedling emergence. Post-anthesis soil moisture stress negatively impacted the plant traits, reducing the duration of the reproductive phenology stage (by 9 days) and seed production (by almost 50%). Unexpectedly, soil moisture stress did not affect most seed or seedling traits. In conclusion, elevated temperatures combined with low soil moisture caused significant declines in seed germination and seedling emergence. On the other hand, the reproductive output of D. brachypodum had low seed variability under soil moisture stress, which might be useful when sourcing seeds from climates with high variability. Even so, a reduction in seed quantity under maternal moisture stress can impact the long-term survival of restored plant populations.

Coconut (Cocos nucifera L.) is an important palm species that serves as the mainstay of several industries and contributes to the livelihoods of millions of smallholder farmers. International exchange of coconut germplasm has been undertaken for several decades to facilitate the conservation of selected varieties within global genebanks and for the distribution to farmers and scientists. In vitro systems are a convenient and an efficient method for the exchange of coconut germplasm. However, it is possible that these tissue culture systems can transfer lethal pathogens causing a threat to the importing countries. In this review, the following topics are discussed: the major disease-causing agents of concern, the various tissues that could be used for coconut germplasm exchange, and the techniques available for the detection and elimination of disease-causing agents from various transmission systems. Additionally, the lack of clear, science-backed guidelines to facilitate the exchange of in vitro coconut materials is raised, along with recommendations for future studies to ensure the safe movement of coconut germplasm without biosecurity risks.

Climate variability is expected to increase due to climate change, with projected increases in temperature and erratic rainfall patterns. These changes will alter the environmental cues sensed by seeds, and therefore will impact plant recruitment. This study investigated the effects of seed functional traits (germinability, germination time, synchrony and seed mass) on germination responses of several sub-tropical native Australian plant species under different environmental factors (water stress, salinity and pH). The effect of a hot water pre-treatment was also tested on Fabaceae seeds with known physical dormancy. Seed traits, environmental factors and seed pre-treatments had significant effects on final germination percentage and germination time. Seed mass and time to 50% germination (t₅₀) were also positively correlated. In contrast, pH did not affect germination and there was no interaction between pH and any of the measured seed functional traits. Some species showed a high thermal tolerance to germination and germination was indifferent to light conditions for all species. Results showed that certain seed functional traits interact with environmental factors to influence germination percentage and time. These findings highlight the importance of considering seed functional traits when determining a species germination response under a changing climate. In addition, the findings provide important knowledge to better guide seed-based land restoration programmes.