盐碱复合胁迫对水稻种子发芽的影响

Effects of mixed saline-alkali stress on germination of rice

  • 摘要: 为研究盐胁迫与碱胁迫复合对水稻种子发芽的影响,采用模拟试验方法,将两种中性盐(NaCl、Na2SO4)和两种碱性盐(NaHCO3、Na2CO3)按照不同比例NaCl:Na2SO4:NaH:CO3:Na2CO3分别为1:1:0:0(A),1:2:1:0(B),1:9:1:0(C),1:1:1:1(D),9:1:1:9(E)混合,每个混合比例设不同总盐浓度(50 mmol·L-1、100 mmol·L-1、150 mmol·L-1、200 mmol·L-1),模拟20种盐碱胁迫环境,以去离子水作为对照(CK),研究不同盐碱混合胁迫对水稻种子发芽的影响。结果表明,水稻种子经两种中性盐混合胁迫溶液培养后,与CK相比,发芽率、发芽势、发芽指数的降幅分别为9.2%~74.4%、10.0%~48.9%、5.6%~55.6%,平均发芽时间延长3.2%~96.4%;随胁迫溶液中碱性盐比例的增加,与CK相比,B-E组发芽率分别降低8.9%~96.5%、15.0%~98.0%、7.5%~98.7%、18.9%~95.7%,发芽势分别降低20.0%~94.4%、13.2%~97.8%、3.3%~100%、36.7%~94.4%,发芽指数分别降低16.7%~94.4%、22.2%~100%、16.7%~100%、27.8%~94.4%,平均发芽时间较CK延长0.8~4.5倍,说明中性盐和碱性盐的混合胁迫溶液对水稻种子发芽的抑制作用更强。将在盐碱胁迫溶液中未萌发的水稻种子转移至蒸馏水中培养7 d后,水稻种子的最终萌发率均达73.33%以上,表明胁迫溶液没有破坏水稻种子的活性,只是暂时性抑制了种子的萌发。试验结果表明:与单施中性盐比较,中性盐与碱性盐混合胁迫作用对水稻种子萌发的抑制作用更明显,且在中性盐与碱性盐混合溶液浓度达200 mmol·L-1时,种子发芽率接近0。

     

    Abstract: Soil salinization has an important effect on seed germination of plants. In recent years, the effects of soil salinization on plant growth and crop yield have become more severe, and the area covered by salinized soil has increased. In order to study the effects of combined salt and alkali stress on the germination of rice seeds, two neutral salts (NaCl and Na2SO4) and two alkaline salts (NaHCO3, Na2CO3) were mixed in five proportions: A (1:1:0:0), B (1:2:1:0), C (1:9:1:0), D (1:1:1:1), and E (9:1:1:9); and each proportion had four concentrations (50 mmol·L-1, 100 mmol·L-1, 150 mmol·L-1 and 200 mmol·L-1) to simulate 20 kinds of saline-alkali stress environments. Deionized water was used as the control (CK). The germination rate, germination potential, final germination rate, germination index, and average germination time of rice seeds were determined during the experiment, and the influences of the various salt solutions on the germination of rice seeds were explored. The results showed that, compared with the control, the germination rate, germination potential, and germination index of rice seeds were reduced by 9.2%-74.4%, 10.0%-48.9%, 5.6%-55.6%, and average germination time was prolonged by 3.2%-96.4% after culture under two neutral salt mixed stress solutions. When the proportion of alkaline salts in the stress solution increased, respectively, compared to the control, the germination rate in the B-E groups decreased by 8.9%-96.5%, 15.0%-98.0%, 7.5%-98.7%, and 18.9%-95.7%; the germination potential decreased by 20.0%-94.4%, 13.2%-97.8%, 3.3%-100%, and 36.7%-94.4%; the germination index decreased by 16.7%-94.4%, 22.2%-100%, 16.7%-100%, and 27.8%-94.4%; and the average germination time was extended by 0.8-4.5 times. These results showed that a stress solution containing two neutral salts and two alkaline salts had a stronger inhibitory effect on the germination of rice seeds than that only containing two neutral salts. After the non-germinated rice seeds in saline-alkaline stress solution were transferred to distilled water and cultured for 7 d, the final germination rates of rice seeds were above 73.33%, indicating that the stress solution did not destroy the activity of rice seeds, but only temporarily inhibited the germination. The experimental results showed that, compared with the single application of neutral salt, the mixed stress of neutral salt and alkaline salt inhibited the germination of rice seeds to a greater extent, and when the concentration of the mixed neutral salt and alkaline salt solution reached 200 mmol·L-1, the seed germination rate was close to zero.

     

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