Effect of Saline Aquaculture Effluent on Salt-Tolerant Jerusalem Artichoke (Helianthus tuberosus L.) in a Semi-Arid Coastal Area of China

An experiment with six treatments: CK1 (rainfed), CK2 (irrigated with freshwater), and 4 treatments of saline aquaculture effluent blended with brackish groundwater at different ratios of 1:1, 1:2, 1:3, and 1:4 (v/v) was carried out during 2004 to assess the effect of saline aquaculture effluent on plant growth and soil properties in the Laizhou region, Shandong Province, China and to determine an optimal salinity threshold for aquaculture effluent. Cumulative evapotranspiration for the saline aquaculture effluent irrigation and non-irrigation treatments was lower than that for the freshwater irrigation treatment. Soil electrical conductivity was higher with respect to saline aquaculture effluent irrigation treatment compared to that with respect to non-irrigation or freshwater irrigation treatment. For Jerusalem artichoke (Helianthus tuberosus L.), in comparison to the freshwater treatment, plant height and aboveground biomass for the 1:3 and 1:4 treatments were constrained, whereas stem width and root biomass were enhanced. Concomitantly, higher tuber yield was obtained for the 1:3 and 1:4 treatments compared to that for CK1 and 1:1 treatments. Nitrogen and phosphorus were higher in tubers of the 1:4 treatment. This study demonstrated that saline aquaculture effluent could be used successfully to irrigate Jerusalem artichoke with higher tuber yield and nutrient removal.

菊芋果聚糖合成关键基因1-SST克隆及序列分析

果聚糖是菊芋的主要贮藏物质,其代谢与产量形成和逆境适应性密切相关。为了解菊芋果聚糖合成代谢的机制,本研究以‘青芋1号’为研究对象,利用同源克隆方法,对果聚糖合成关键基因1-SST克隆及序列分析。结果表明,1-SST基因全长为3 925 bp,CDS大小为1 890 bp,由5个内含子和6个外显子组成。经生物信息学分析,预测1-SST蛋白分子量70 934.40 Da,等电点5.10,有两个属于糖基水解酶32家族的保守区,属于亲水性蛋白,以延伸结构(24.48%)和无规则卷曲(56.76%)为主要二级结构,在质膜外行使功能。系统进化分析表明,菊芋1-SST基因与向日葵遗传距离最近,与龙舌兰等不同科不同属的植物进化距离较远。本研究基于对菊芋中调控果聚糖合成代谢1-SST基因的克隆与生物信息学分析,为高等植物果聚糖代谢途径研究奠定一定的理论基础。

干旱胁迫下菊芋果聚糖代谢生理响应特征

菊芋(Helianthus tuberosus L.)以果聚糖作为主要储藏物质,果聚糖有可能在适应干旱胁迫的生理调控中起着重要作用,其干旱条件下响应机制有待进一步研究。本实验以敏感型‘青芋1号’和抗旱型‘青芋3号’为材料,采用人工控水的方法进行干旱胁迫,控水后于不同时期取样并测定植株果聚糖含量及聚合度、果聚糖代谢相关酶活性等生理指标。结果显示:菊芋幼苗在干旱胁迫后,敏感型品种游离糖含量变化明显且处理组果聚糖含量低于对照组,而抗旱型品种的对照组和处理组的果聚糖含量在胁迫前期表现相反,后期同步升高。2个品种菊芋叶片的果聚糖合成酶活性均表现为处理组高于对照组,且抗旱型‘青芋3号’更高,胁迫前期2 d时SST活性达2801.18 kat,后期10 d时IVN、FEH活性分别达到7540.34 kat、7332.36 kat,说明菊芋受到胁迫后,叶片中果聚糖合成酶活性迅速提高,以快速积累果聚糖并增加果聚糖的聚合度,同时向贮存器官快速转运,增强植物抗旱能力;随着胁迫程度的加深,植株通过水解作用将贮存的果聚糖解链,释放出游离单糖以提升渗透调节能力。