河西绿洲菘蓝生长、光合特性及品质对膜下滴灌调亏的响应

通过菘蓝的水分控制试验(2016年),研究了不同生育期不同梯度调亏灌溉对河西绿洲菘蓝生长、光合特性及产量品质的影响。试验以河西走廊中部张掖市水务局国家重点灌溉试验站为平台,甘肃农业大学中草药系自繁菘蓝种子为供试材料,采用不同生育期和不同梯度调亏灌溉方式二因素随机区组试验设计,共9个处理。在每个生育期测定菘蓝光合参数,收获后测定新鲜板蓝根产量及品质,为河西绿洲灌区合理种植和提高菘蓝产量品质及可持续发展提供理论依据。结果表明:(1)营养生长和肉质根生长期水分亏缺显著降低了菘蓝叶片净光合速率、蒸腾速率和气孔导度,且降幅随水分亏缺程度加大而增大。(2)水分亏缺造成菘蓝产量降低,调亏处理中肉质根成熟期轻度水分亏缺产量最高(7 342.05kg/hm~2),较充分灌溉降低5.32%(P0.05)。(3)苗期轻度水分亏缺水分利用效率最高(2.14kg/m~3),肉质根成熟期轻度水分亏缺次之。(4)肉质根成熟期轻度调亏处理的菘蓝综合品质最优,其菘蓝靛蓝、靛玉红、(R,S)-告依春含量比生育期充分灌溉提高了0.09,0.41,0.007 8mg/g,但多糖含量下降3.37mg/g。因此,综合考虑菘蓝产量、水分利用效率及品质等指标,肉质根成熟期进行轻度调亏,即该时期土壤相对含水率为60%~90%,可以作为河西走廊绿洲灌区菘蓝最优栽培灌溉的一种方式。

Responses of Growth, Photosynthetic Characteristics and Quality of Isatis in Hexi Corridor to Mulched Drip Irrigation Under Water Deficit

The field experiment was carried out to study the effects of different growing stages and different gradient way of regulated deficit irrigation (RDI) on growth, photosynthetic characteristics, yield and quality in Isatis indigotica of the Hexi oasis. Field experiments were conducted from 2016 in the National Key Irrigation Experimental Station of Zhangye Water Resources Bureau in Central Hexi Corridor District, from numerous The Isatis indigotica seeds, bred by the Department of Chinese herbal medicine of Gansu Agricultural University, were used as tested materials. Two-factor randomized blocks were designed with nine treatments, including different growing periods and different gradient way of RDI. Each treatment had three plots as repeats in a completely random-sized design. In each growth period, the photosynthetic parameters of Isatis indigotica were determined, and after the harvest, yield and quality index were measured on fresh Radix Isatis. The results would provide a theoretical basis for reasonable planting and sustainable development of Isatis indigotica in Hexi oasis. The results showed that:(1) In the periods of vegetative stage and fleshy root growth, the water deficit significantly reduced the Isatis leaf net photosynthetic rate, transpiration rate and stomata conductance, and the declines increased with the raising water deficit regulation (WDR) level. (2) The highest yield was achieved under light WDR (7 342.05 kg/hm²) in the mature period of the regressed deficit, which was 5.32% lower than that of the full irrigation (P> 0.05). (3) The highest utilization efficiency of WDR (2.14 kg/m³), was followed by mild WDR in the flesh root maturity stage. (4) The quality of Isatis root was greatly improved especially in maturity period by mild WDR. The indigo, indirubin and (R,S)-goitrin content of Isatis root were improved by 0.09, 0.41 mg/kg and 0.007 8 mg/g,but content of polysaccharide reduced by 3.37 mg/g, respectively. Therefore, considering the yield, water use efficiency and quality, the fleshy root maturity could be implemented with RDI slightly, i.e., the relative water content of the soil was 60%~90% during this period, which could be used as the optimum way of cultivating irrigation.