Over 60 % of the world's plants are concentrated in tropical rainforests, and the seeds of these plants are unsuitable for storage at low temperatures and humidities. For example, many seeds of the palm family go bad within a month or even a few days of falling to the ground if they do not germinate.
然而，全球植物 60 % 以上集中在熱帶雨林，而這些植物的種子並不適合低溫及乾燥的保存環境，例如許多棕櫚科植物的種子，落下來一個月、甚至幾天內不種植就會壞死。