关键词: 小麦, CO₂浓度升高, 干旱胁迫, 抗氧化酶类

Abstract: In genus Pinus,there are approximately 110 species which can be classified into two groups according to the modes of their seed dispersal,i.e.,winddispersed and animal-dispersed.The former is in absolute majority,with the seeds small and having relatively large wings that have the potential to carry by the wind well beyond the canopy of parent trees,while the latter includes about 23 species,often with large,edible and wingless or nearly wingless seeds,and distributed in barren or infertile habitat,and in high elevation mountains.The seeds of nine species in this group are known to be dispersed by animals,and those of the other 14 species are presumed to be.Animal dispersers are corvidae (e.g.,jay and nutcracker) and rodents (e.g.,chipmunk, mouse,and squirrel).They store the seeds separately in many caches,with one or several seeds per cache,and the remained seeds may germinate and be dispersed.Many of the cache microhabitat are beneficial to seed germination,a directed dispersal.The dispersal distance may be several meters (by rodents) or kilometers (by birds).Tree cluster (clumping) or multitrunk often occurs for animal-dispersed pines,due to the germination of several seeds in one cache.The seeds in most caches are recovered and eaten by hoarders,a post-dispersal predation.Some wind-dispersed pines with large seeds are not dispersed very far,and the seeds may be cached by animals and dispersed again,a secondary dispersal.Such pines can be also classified as a type of “wind plus animal dispersed pines”.A mutualism exists between dispersing animals and pines.

Key words: Triticum astivum, Elevated CO₂ concentration, Drought stress, Antioxidative enzymes