碱胁迫对花生幼苗根系形态及干物质累积的影响

Effects of alkaline stress on root morphology and dry matter accumulation characteristics of peanut seedling

探讨花生对碱胁迫的响应机制及耐碱阈值,可为盐碱地花生合理种植提供依据。采用盆栽试验,研究了不同碱性土壤(pH值为8.5、9.0和10.0)对两个不同类型花生品种(大花生花育22和小花生花育20)幼苗根系形态、农艺性状及植株干物质累积的影响。结果表明:(1)pH8.5处理对花生植株的抑制作用相对较小,两个花生品种仅根长及植株干重略低于对照(pH6.0处理)。(2)随土壤pH值升高,花生根系受抑制程度增加。pH9.0条件下,花育20的总根长、根体积及根表面积较对照分别降低73.3%、61.3%和65.5%,花育22分别降低69.6%、55.1%和63.9%。pH10.0条件下,花育20上述三个指标较对照分别降低98.9%、81.1%和96.6%,花育22分别降低98.8%、85.1%和96.8%。花生直径0~1mm根系长度、体积及表面积所占比例随pH值升高呈降低趋势,直径2mm以上根系所占比例增加,pH10.0处理更为明显。(3)高pH碱胁迫(pH9.0和10.0)抑制了花生地上部生长,表现为叶面积下降、各器官干物质重及根冠比降低。pH9.0条件下,花育20和花育22的整株干重分别比对照降低43.0%和29.4%;pH10.0条件下,干重分别降低74.8%和69.7%。综合各性状,花生种植土壤pH不宜超过8.5,花育22耐碱性好于花育20。

Soil alkaline stress is one of the main environmental factors affecting plant growth. Peanut （ Arachis hypogaea） , an important oil and economic crop in China, has been deemed to be with alkaline stress resistance. However, its response mechanisms to soil alkaline stress are still unclear. A pot experiment was used to investigate the effects of soil pH on root morphology and growth development characteristics at seeding stage of two peanut vari-eties. The soil pH were 8.5, 9. 0, 10. 0 and 6.0（ CK） . The tested large seed variety Huayu 22 and small seed va-riety Huayu 20 were two main popularized varieties in Shandong Province, China. The results showed that, （1） the inhibition of growing development of peanut were relatively small in pH8. 5 treatment. Only root length and plant dry weight of peanut in pH8.5 soil were lower than those of CK. （2） Inhibition degree of peanut roots increased with the increasing of soil pH. In pH9. 0 treatment, total root length, root volume and root surface area were re-duced by 73.3% , 61.3% and 65.5% for Huayu 20 and reduced by 69. 6 % , 55. 1 % and 63.9 % fo rH u a y u 22, when compared with CK respectively. In pHlO. 0 treatment, the 3 indexes mentioned above were 98. 9 % , 81. 1 % and 96. 6% lower for Huayu 20 and 98. 8 % , 85. 1 % and 96. 8 % lower for Huayu 22 than CK. The ratio of root ength, root volume and root surface area with diameter 0 - 1 mm to total root decreased and the ratio with diameter ≥2 mm increased in pH9.0 and pH10. 0 treatments. （3） Alkaline stress of high pH inhibited over ground part of peanut seedling. Leaf area, dry weight of plant organs and root shoot ratio were decreased significantly in pH9. 0 and pH 10.0 treatments. Dry weight per plant in pH9. 0 treatment was decreased by 43. 0% for Huayu 20 and 29. 4% for Huayu 22 compared with CK. In pH10. 0 treatment, dry weight per plant was decreased by 74. 8 % for Huayu 20 and 69. 7% for Huayu 22 compared with CK. Taken into consideration of all characteristics, soil pH ex-ceeded 8.5 was not suitable for planting peanut. The peanut variety Huayu 22 had a greater alkaline tolerance than Huayu 20.