干旱胁迫对降香黄檀(Dalbergia oderifera)种子发芽及幼苗生长的影响研究

Research on the Germinating and Growing of Dalbergia oderifera Seedling under Drought Stress

通过采集当年降香黄檀种子进行苗床播种试验,试验设计1 d、3 d、5 d、7 d以及CK浇水时间梯度,以对比不同干旱胁迫下降香黄檀生长差异。结果得到,不同干旱胁迫程度均会对降香黄檀幼苗的发芽率、发芽时间、叶量、根长等产生影响。此外,随着干旱胁迫逐渐增加,叶绿素相对含量、叶绿素相对含量增长率均下降;3 d组株高较高,CK组株高较低。5 d组基径较大,干旱程度减轻或加重均使植株基径显著下降;地上(下)生物量、全株生物量较高和较低均为3d组和CK组,3d组分别较CK组高4.5倍、3.2倍和4.5倍;1d和3d组幼苗根系根瘤数较多,而CK较少,干旱胁迫程度增加植株根系根瘤数逐渐下降;1d脯氨酸含量较低(7.4μg/g),而CK含量较高(16.3μg/g),CK组脯氨酸含量是1d的2.2倍,叶片脯氨酸含量随着干旱程度的增加而递增,而植物根冠比随干旱胁迫程度的变化与脯氨酸一致。

Five watering time levels of 1d,3d,5d,7d and CK were designed to obtain the growth differ-ence of Dalbergia oderifera seedling（ seeds were collected from current year and seeded on the seedbed）which were under drought stress. The results show, different drought stress level impacted on germinationrate, germinating time, the number of leaves, length of roots and so on. In addition, chlorophyll relativecontents and the growth rate of chlorophyll relative contents declined when drought stress was increasinggradually to the height of seedling, 3d was the highest while CK was the lowest group. 5d had the big-gest stem basal diameter, and the stem basal diameter about all of the groups declined significantly whendrought stress went up 3d was always the highest one at above - ground biomass, under - ground bio-mass and whole plant biomass of the Dalbergia oderifera seedling, and the lowest one was CK at the 3 in-dexes of above - ground biomass, under - ground biomass and whole plant biomass above. 3d was 4.5,3.2 and 4.5 times higher than CK at above - ground biomass, under - ground biomass and whole plantbiomass of the Dalbergia oderifera seedling respectively to the number of root nodules, the most oneshapped in ld and 3d. Furthermore, the number of root nodules reduced when drought stress level was in-creasing. The highest content of proline was CK（7.4 μg/g） while the lowest one was ld（ 16.3 μg/g）.Root cap ratio as well as the changed rule of proline was increasing gradually when the drought stress went up.