沙地云杉和青海云杉种子萌发和幼苗生长对干旱盐碱胁迫的响应

利用控制实验研究了水分、盐分生态因子对沙地云杉和青海云杉种子萌发和幼苗生长的影响,以探索沙地云杉和青海云杉种子对水分、盐分生态因子的适应性。结果表明:(1)水分胁迫和盐分胁迫对沙地云杉和青海云杉种子萌发具有明显的抑制作用,可显著的降低种子的发芽率,两种云杉种子对水分胁迫的临界值和极限值分别是-0.03、-0.15 MPa和-0.5、-0.58 MPa;对盐分胁迫的临界值和极限值分别是78、148 mmol/L和284、345mmol/L;其幼苗长度随着渗透势和NaCl浓度的增加而显著减小。(2)沙地云杉和青海云杉种子恢复发芽率及恢复后的幼苗长度随着渗透势和NaCl浓度的增加先增加后减少。(3)在相同的水势条件下,PEG溶液比等渗的NaCl溶液对沙地云杉和青海云杉种子萌发具有更大的抑制作用,种子萌发过程中渗透胁迫比离子毒害的抑制作用更大。研究发现,沙地云杉和青海云杉种子对水分和盐分胁迫表现出不同程度的耐受性,两者对盐分胁迫的忍耐能力超过对水分胁迫;而且青海云杉种子比沙地云杉更耐旱、耐盐;早期的低盐和充分的水分条件是沙地云杉和青海云杉存活的关键。

Response of Picea mongolica and Picea crassifolia Seed Germination and Seedling Growth to Drought and Salt Stress

The adaptability of Picea mongolica and Picea crassifolia seeds to ecological factors was studied by the effects of water and salt stress on the germination characteristics and seedling growth.The results showed that:(1)The restriction of PEG-6000 and NaCl stress to seed germination and seedling growth of P.mongolica and P.crassifolia seeds were more significant (P<0.05).The critical value and maximum value of water stress were -0.03 MPa,-0.15 MPa and -0.5 MPa,-0.58 MPa;the critical value and maximum value of salt stress were 78 mmol/L,148 mmol/L and 284 mmol/L,345 mmol/L.(2)After salt stress relieve,the recovery germination rate(RGR) decrease after increase first with the increase of osmotic potential and NaCl concentration.(3)At same water potential,the PEG-6000 solutions were inhibitorier than NaCl solutions to seed germination and seedling growth;the osmotic stress was the dominant restrain factor and ionic toxic action was less than it.The research found that P.mongolica and P.crassifolia seeds showed certain tolerance to water and salt stress,their tolerant ability to salt stress was strong than to water stress.P.crassifolia seeds tolerant ability to salt and water stress was strong than that of P.mongolica;Low salinity and sufficient water supply are the most important for the survival of P.mongolica and P.crassifolia seeds.