小麦秸秆浸提液和腐解液对棉花种子发芽及幼苗生长的化感效应

于2014年在江苏南京江苏省农业科学院人工气候室内进行水培试验,以中棉所50为材料,设置5个小麦秸秆浸提液和腐解液含量(质量分数1.0%,3.0%,5.0%,7.0%和10.0%),研究小麦秸秆浸提液和腐解液对棉花种子萌发和根系发育的影响,明确小麦秸秆对棉花生长的化感效应。结果表明:随秸秆浸提液和腐解液含量升高,浸提液和腐解液中氮、磷、钾和总酚酸含量持续升高;相同含量下,腐解液中氮和磷含量与浸提液差异不显著,而钾和总酚酸含量高于浸提液。≤7.0%的浸提液和≤5.0%的腐解液只延迟了棉花种子发芽时间,并未影响发芽率;高于此含量时,两者不仅延迟发芽时间,而且降低发芽率。浸提液和腐解液含量高达3.0%后显著抑制棉花主根伸长、缩短侧根发生区、减少侧根数量、降低根系总表面积和总体积,并随含量增加,抑制和降低作用显著增强。低含量的小麦秸秆浸提液与腐解液显著促进根系呼吸速率和根系活力,当浸提液与腐解液含量高于3.0%时,根呼吸速率与根活力显著降低,而MDA含量却随含量提高而显著增加。小麦秸秆浸提液和腐解液中总酚酸和养分含量与其化感效应有关,高含量的浸提液和腐解液抑制棉花种子萌发、根系形态指标建成和根系呼吸,同等浓度下,小麦秸秆腐解液对棉花的化感效应强于浸提液。

Allelopathic Effects of Wheat Straw Extract and Decomposition Liquid on Cotton Seed Germination and Seedling Growth

To study effects of wheat straw on cotton(cv. CCRI 50) seed germination and root growth, we carried out an experiment with different concentrations of water extract and decomposition liquid of wheat straws in the environment chamber of Jiangsu Academy of Agricultural Sciences at Nanjing. Results showed that, contents of nitrogen, phosphorus, potassium and total phenolic acids increased with the increasing water extract and decomposition liquid concentrations (mass fraction). With the same concentration, there were no obvious difference about nitrogen and phosphorus contents between water extract and decomposition liquid, but total phenolic acids and potassium contents in decomposition liquid were higher than that in water extract. The water extract and decomposition liquid, not exceeding 7.0% (mass fraction) and 5.0%, individually, only delayed the germination time of cotton seed, but had no effects on germination rate. However, over 7.0% and 5.0% individually, they led to not only a delay of germination time, but also a decrease in germination rate. The water extract and decomposition liquid, over 3.0%, inhibited root elongation and lateral root development, which appeared as decrease of the lateral root number, total root surface area, and total root volume, but increase of average root diameter. The reduction of lateral root mainly resulted from short length of branched root zone. The water extract and decomposition liquid played a positive role at lower concentrations(below 3.0%), but an inhibitory role at higher concentrations (over 3.0%) on root respiration and root vigor; however, they had opposite effects on the content of malondialdehyde. Allelopathic effects of the extract and decomposition liquid were related to the total phenolic acids, nitrogen, phosphorus and potassium contents, which could inhibit seed germination, root morphology formation and root respiration. The allelopathic effects of decomposition liquid were higher than that of water extract.