盐胁迫对柚、福橘种子萌发和幼苗生长的影响

Effects of salt stress on seed germination and seedling growth of pomelo and citrus

通过水培和沙培试验,研究了盐胁迫对柚、橘种子萌发和幼苗生长的影响.结果表明:(1)20-40mmol·L-1NaCl胁迫不影响坪山柚和福橘种子萌发率、芽及胚根生长,但发芽时间延长.(2)NaCl浓度≥60mmol·L-1,显著降低坪山柚和福橘种子萌发率、芽及胚根长度,种子相对盐害率显著升高;相同浓度NaCl胁迫,坪山柚种子相对盐害率低于福橘,芽及胚根受抑制程度比福橘低.(3)NaCl浓度≥80mmol·L-1,坪山柚和福橘幼苗株高、叶面积、地上部干重、根部干重和根冠比(坪山柚根冠比在NaCl浓度为120mmol·L-1时)显著下降;同一浓度NaCl胁迫,坪山柚幼苗生长受抑制程度比福橘小.(4)坪山柚地上部及根部较低的Na+和Cl-含量及保持较高的根冠比是坪山柚幼苗耐盐胁迫的主要原因.

Effects of NaCl stress on seed germination and seedling growth of Citrus grandis Osbeck cv.Pingshanyou and C.reticulata Blanco cv.Fuju were studied through solution culture and sand culture.The results showed that 20-40 mmol·L-1 of sodium chloride (NaCl) had no effect on the seed germination percentage, sprout length and radicle length of Pingshan pomelo and Fuju, but the time needed to complete the germination was lengthened. NaCl concentration higher than 60 mmol·L-1 decreased final germination percentage, a significant decrease in the seed germination percentage and length of spout and radicle and an increase in the relative injury rate were found in Pingshan pomelo and Fuju when treated with >60 mmol·L-1 NaCl. The relative injury rate of Pingshan pomelo was lower than Fuju and the inhibited extent of sprout and radicle was also lower than that of Fuju under the same NaCl concentration. NaCl salinity drastically decreased seedling plant height, leaf area,shoot dry weight, root dry weight and root/shoot ratio of Pingshan pomelo and Fuju when NaCl concentration >80 mmol·L-1 (the ratio of root/shoot was not decreased until NaCl concentration reached 120 mmol·L-1). The inhibited extent of seedling growth of Pingshan pomelo was lower than that of Fuju. The lower contents of Na+ and Cl- in both root and the above ground parts and the keeping of higher shoot/root ratio are the main reasons for Pingshan pomelo seedling to have better salt tolerance.