种子大小和干旱胁迫对文冠果幼苗生长的影响

Effects of seed size and drought stress on growth of Xanthoceras sorbifolia seedlings

【目的】研究种子大小和干旱胁迫对文冠果种子发芽率和幼苗生长的影响,为文冠果育苗和人工林培育提供理论依据。【方法】以文冠果大种子（单粒种子质量〉1.0g）、中等种子（单粒种子质量0.6-1.0g）、小种子（单粒种子质量〈0.6g）为研究对象,采用室内完全随机试验方法,以聚乙二醇（PEG）-6000溶液模拟干旱胁迫对各水势条件下（对照,-0.2,-0.6 MPa）不同大小文冠果种子的发芽率及幼苗生长状况、生物量积累与分配进行研究。【结果】种子大小和干旱胁迫对文冠果种子发芽率有显著影响,大种子相对于中等种子和小种子,具有更高的发芽率;在-0.2 MPa水分处理下,大种子发芽率为100%,中等种子和小种子发芽率分别为97.92%和94.79%;在-0.6MPa水分处理下,大种子发芽率为95.83%,而小种子发芽率为88.55%。种子大小和水分条件对文冠果幼苗生长量也有显著影响,大种子相对中等种子和小种子幼苗有较大的生长量;随着水势的降低,不同大小种子起源的文冠果幼苗生长量逐渐降低。种子大小和水分条件对文冠果幼苗生物量积累及分配均有显著影响,大种子相对中等种子和小种子幼苗有更大的生物量积累。在不同水分条件下,大种子幼苗将更多的生物量投入到了叶片,而小种子幼苗将更多的生物量投入到根系。【结论】在干旱地区文冠果播种造林中,尽可能选择种粒质量大于1.0g的种子以提高成活率。

【Objective】This paper studied the effects of seed size and drought stress on seedling growth of Xanthoceras sorbifoliato provide basis for seedling and plantation cultivation of Xanthoceras sorbifolia.【Method】In this paper,a completely random experiment was conducted on the survival rate,growth,biomass accumulation and allocation of seeds with sizes of big（〉1.0g）,medium（0.6-1.0g）and small（〈0.6g）under three water conditions of control,-0.2and-0.6MPa.【Result】Seed size and water condition had significant effects on germination of X.sorbifolia seed.Big seeds had higher germination rate than medium and small seeds.With the water treatment of-0.2 MPa,the germination rate of big seeds was 100%,while those of medium and small seeds were 97.92% and 94.79%,respectively.Under the water treatment of-0.6 MPa,the germination rate of big seeds was 95.83%,while that of small seeds was88.55%.Seed size and water condition also had significant effects on growth of X.sorbifoliaseedlings,and the seedlings from big seeds had larger growth than the seedlings from medium and small seeds.With the decrease of water potential,growths of seedlings with different seed sizes decreased gradually.Biomass accumulation and allocation of seedlings were also significantly affected by seed size and water condition.The seedlings from big seeds had larger biomass allocation than the seedlings from medium and small seeds.Under different water conditions,the seedlings from big seeds allocated more biomass to leaf,while the seedlings from small seeds allocated more biomass to root.【Conclusion】In afforestation for arid region,large seeds with size of〉1.0g were suggested to improve survival rate.