Influencing Factors of Seed Long-distance Dispersal on a Fragmented Forest Landscape on Changbai Mountains,China

Seed long-distance dispersal(LDD) events are typically rare, but are important in the population processes that determine large-scale forest changes and the persistence of species in fragmented landscapes. However, previous studies focused on species dispersed via animal-mediated LDD, and ignored those dispersed by wind. The aim of this study was to assess the effects of canopy openness, edge, seed source, and patch tree density on the LDD of seeds by wind in forest. We collected birch seeds, a typical wind-dispersed species, throughout a larch plantation. We then assessed the relationship between birch LDD and each factor that may influence LDD of seeds by wind including distance to edge, canopy openness size, distance to mature forest, and the tree density of the larch plantation. We used univariate linear regression analysis to assess the influence of those factors on birch LDD, and partial correlations to calculate the contribution of each factor to LDD. The results showed that both canopy openness and edge had significant influences on birch LDD. Specifically, a negative relationship was observed between distance to edge and birch LDD, whereas there was a positive correlation between canopy openness size and LDD. In contrast, the distance to the mature forest was not correlated with birch LDD. Our results suggest that patch tree density could potently affect the probability of LDD by wind vectors, which provides novel and revealing insights regarding the effect of fragmentation on wind dynamics. The data also provide compelling evidence for the previously undocumented effect of habitat fragmentation on wind-dispersed organisms. As such, these observations will facilitate reasonable conservation planning, which requires a detailed understanding of the mechanisms by which patch properties hamper the delivery of seeds of wind-dispersed plants to fragmented areas.

No evidence of seed transmissibility of Tomato yellow leaf curl virus in Nicotiana benthamiana

最近有研究报道番茄黄化卷叶病毒在番茄中可以通过种子传播,这个结论与之前的普遍观念是相反的。为了确定该病毒的种子传播性是否是在不同寄主植物中具有普遍性,我们检测了该病毒在本氏烟中通过种子的传播能力。实验结果证明在我们的实验条件下,番茄黄化卷叶病毒在本氏烟中没有种子传播性,从而说明该病毒在不同寄主植物中的种子传播性是不同的。不同的生长条件造成影响的可能性也需要被考虑。