十万个为什么·科学阅读30篇（4）

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为什么沙漠植物只在罕见的暴雨后开花？

Desert plants like ocotillo and desert lilies remain dormant for months or even years underground.
Their seeds contain biochemical inhibitors that prevent germination until heavy rain washes them away.
Soil moisture must reach a critical threshold to trigger hormonal signals for rapid growth.
This adaptation avoids wasting energy on flowers if rain is too brief or shallow for root establishment.
Some species bloom within 48 hours after rainfall, completing their entire life cycle in under six weeks.
Bees and moths synchronize their activity with these short-lived floral displays for pollination.
Scientists study seed coat chemistry to understand how drought tolerance evolved in arid zones.
Climate change may disrupt this timing by altering rainfall intensity and seasonal distribution.
Remote sensing helps track bloom events across vast deserts where ground observation is difficult.
These ephemeral blooms support entire food webs, including insects, birds, and small mammals.