切花月季失水胁迫耐性差异与内肽酶活性的关联

Relationship between Endopeptidase Activity in Petals and Tolerance to Water Deficit Stress of Two Cut Rose Cultivars

选用切花月季耐失水胁迫品种'Samantha'和中度耐失水胁迫品种'Belami',采用带枝花和离枝花两种形式,在22～25℃、RH 30%～50%、80 μE*m-2*s-1荧光灯照光条件下进行了0～60 h的失水胁迫处理.结果显示:①失水胁迫中花枝弯颈率的增加,'Samantha'快于'Belami',同一品种带枝花快于离枝花,但复水后恢复率的降低前者慢于后者,同一品种带枝花慢于离枝花.胁迫过程中,带枝花、离枝花都出现了恢复率快速降低的拐点,前者晚于后者.对应于花枝复水恢复率快速降低的拐点,水势值同一品种的带枝花、离枝花基本相同.②两品种花瓣中游离氨基酸含量均是带枝花、离枝花快速上升的转折点与其相应的复水率迅速降低拐点相吻合.③胁迫诱导的花瓣内肽酶活性上升,'Samantha'明显晚于'Belami',同一品种带枝花早于离枝花.两品种带枝花和离枝花花瓣内肽酶活性诱导上升的转折点与其相应的复水恢复率迅速降低拐点相一致.④胁迫诱导引起的花瓣中金属蛋白酶和丝氨酸蛋白酶活性的变化均是'Samantha'显著低于'Belami'.由此推测,切花月季品种间失水胁迫耐性差异可能与胁迫对花瓣中金属蛋白酶和丝氨酸蛋白酶活性诱导的差异有关.

This work was aimed to investigate to relations between tolerance to water deficit stress （WDS） and the activity and type of endopeptidase in different cultivars of Cut roses （Rosa hybrid）. Two cultivars, ＇ Samantha＇ with the strong tolerance to WDS, and ＇ Belami＇ with the medium one, were used as materials, and WDS treatment was carried out for 0 -60 h under the conditions of 22 -25℃, RH 30% - 60% , and 80 μE ·m^-2· s^-1 To make different process of WDS, we treated the two cultivars separately with two manners, namely flowers with and without branches in the same condition of WDS above. The results showed that, ① the decrease of flower recovery percentage was much slower in ＇ Samantha＇ than in ‘Belami＇ , and was slower significantly in the flowers with branches than without branches in a cultivar, while the opposite tendency was obtained on the increase of flower bent neck percentage during WDS. A turning point, in which recovery rate of flowers was going to be decreasing rapidly, was observed in both flowers with and without branches, and the occurrence of the turning point was later in ‘Samantha＇ than in ＇ Belami＇. However, the value of water potential was almost the same in a cultivar, corresponding to the turning point of recovery rate. ②The turning point of quick climbing of free amino acid content in petals was also observed in the flowers of both cultivars, including the two manners, with or without branches separately during WDS, and these points were identical with the turning points of their recovery rate. ③ WDS-induced increase of endopeptidase activity was later in ‘Samantha＇ than in ‘ Belami＇ , and it was earlier in the flowers with branches than without branches in a cultivar. Interestingly, the turning points of quick increase of endopeptidase activity induced by WDS in both cultivars with or without branches were consistent with the turning points of their recovery rates.④Changes of both metallo-proteinase and serine proteinase activities of petals induced by WDS were significantly smaller in ‘ Samantha＇ than in ‘ Belami＇ The results above suggested that the difference of tolerance to WDS between different cuhivars mi and serine proteinase activitives in petals induced be related to the different changes of metallo-proteinase WDS.