驯化处理对海水胁迫下玉米幼苗生长特性的影响

Effects of acclimation on the growth characteristics of maize seedlings during seawater stresses

为了探讨海水灌溉时提高植物耐受盐分胁迫的有效调节措施,以抗性玉米品种农大108为材料,研究了用20%和70%海水分别驯化的萌发种子和萌发期幼苗在生长后期50%海水胁迫过程中某些生理指标的变化。结果表明:在海水处理过程中,叶绿素和类胡萝卜素含量、光合速率和幼苗鲜质量明显下降,其中种子驯化能减弱胁迫对上述特性的不利影响,70%海水驯化种子缓解了对叶绿体色素和光合作用的破环,20%海水驯化种子减轻了幼苗鲜质量的降低;叶绿素a/叶绿素b(chla/chlb)、根系活力、幼苗干质量和根冠比明显上升,其中驯化处理有利于胁迫下幼苗根系活力和根冠比的升高,20%海水驯化种子促进了幼苗干质量和根冠比的增加,70%海水驯化幼苗对chla/chlb和根系活力的促进作用比20%海水驯化种子稍微明显一些。说明在不同发育阶段采取合理的驯化方式可以提高植物生长过程中对海水胁迫的适应能力,从而改善植物对灌溉海水的利用效率。

The variance of some physiological indexes of late seedlings of stress-tolerant maize variety ＂nongda 108＂ during the half-seawater stress was studied after its germinated seeds and early seedlings were pre-treated for 12 hours by 20% and 70% seawater respectively in order to determine some effectively regulating measures for enhancing salinity-tolerance of seawater-irrigated plant. The result shows ：the seawater stresses lead to decline of chlorophyll and carotenoid contents and photosynthetic rate and fresh weight of seedlings, but seed hardening can alleviate above adverse aspects caused by seawater, 70% seawater-treated seeds reduce the damage of chloroplast pigments and photosynthesis and 20% seawater-treated seeds slows down the reduction of fresh weight especially. However, chlorophyll a/chlorophyll b and root activity and dry weight of seedlings and root/shoot ratio evi- dently rise in the stress, pre-treatments benefit the ascending root activity and root/shoot ratio, 20% seawatertreated seeds particularly accelerate the increase of dry weight and root/shoot ratio and 70% seawater-treated seeds slightly better promote chlorophyll a/chlorophyll b and root activity than 20% seawater-treated seeds do. This means that adopting reasonable acclimation in certain developing phases can enhance the adaptability to seawater stress in the growth stages and then improve the using efficiency of seedling to irrigated seawater.