梭梭种子萌发对干旱和盐分胁迫的响应

Seed Germination Responses of Haloxylon ammodendronto Drought and Salt Stress

以荒漠严酷环境下植物种子适应性为科学问题,运用生理生态学原理,以采自不同生境的5个梭梭种群的种子为试材,在实验室模拟基础上,研究了梭梭种子萌发对干旱和盐分胁迫的响应规律。结果表明:在PEG溶液和盐溶液中,来自不同生境梭梭种群的种子其萌发率均随水势的降低而下降,分别到-2.26MPa和-4.15MPa时,所有种群梭梭种子萌发率均接近于零。在水势相等的情况下,所有种子的萌发均受到NaCl和等渗PEG溶液的抑制,并且等渗NaCl溶液对梭梭种子萌发的抑制程度要显著小于PEG溶液,说明渗透胁迫是影响梭梭种子萌发的主要因素。当解除盐胁迫后,梭梭种子恢复萌发率较高,表现出一定程度的高盐诱导休眠现象。水势相等条件下,PEG溶液中恢复萌发率低于NaCl溶液中恢复萌发率,表明离子效应对梭梭种子的影响要小于渗透胁迫。可见,梭梭种子萌发对盐分和干旱胁迫适应性强,是该种群恢复和保育的基础。

Using physiological principles of ecology,focused on the seed suitability of plant in the harsh desert environment,and based on laboratory simulation,with seeds of Haloxylonammodendronfrom different habitat as materials,the effect of drought and salt stress on seed germination of Haloxylon ammodendron was studied.The results showed that a trend could be observed in all seeds from different populations in PEG and saline solutions.All germination rate decreased with decreasing water potential.When the water potential reached-2.26 MPa and-4.15 MPa separately,the germination rates in all population were close to 0.The inhibitory effect on germination of all the seeds could be detected in NaCl and Iso-osmotic PEG.And the inhibitory effect of Iso-osmotic NaCl was lower than PEG.It showed that the osmotic stress was the main factor that affect the germination of H.ammodendron.When salinity stress was alleviated,the germination of H.ammodendroncould recover quickly.And it meant that hypersaline conditions could induce dormancy of these species.In the equal water potential,the re-germination rate in PEG solution was lower than in NaCl.It included the effect of ion stress on germination was lower than osmotic stress.Therefore,H.ammodendron＇s high adaptability of seed germination to drought and salinity stress was the basis of the population＇s restoration and conservation.