Foliar manganese in the health and lignin quality of conventional and glyphosateresistant soybean seeds

Manganese may be associated with plant resistance to fungi, either through lignification or direct inhibition. The aim of this study was to evaluate the foliar application of Mn on the incidence of fungi and the levels of Mn and lignin in soybean seeds from conventional cultivars and their transgenic glyphosate-resistant derivatives (RR). The test was conducted at the Federal University of Lavras, in the state of Minas Gerais, Brazil, using a randomized block design with three replications in a 4 x 4 x 2 factorial scheme, comprising four soybean cultivars, two conventional and their RR derivatives (BRS Celeste and BRS Baliza RR; BRSGO Jataí and BRS Silvânia RR), four foliar dosages of Mn (0, 200, 400 and 600 g Mn ha-1) and two application stages (R1 and R3). Prior to, and after six months of storage, the seeds were subjected to a health test (Blotter test). The levels of Mn in the seeds and lignin in the seed coat were determined. It was found that foliar application of manganese affords a lower incidence of Cercospora kikuchii, Fusarium spp. and Aspergillus spp. in the soybean seeds produced. Foliar applications of Mn in the soybean, both at the R1 and R3 stages, translocates to the seeds, but does not affect lignin production in the seed coat. Levels of lignin in the seed coat of the soybean are lower in the conventional cultivars, Celeste and Jataí, in relation to their transgenic glyphosate-resistant derivatives, Baliza RR and Silvânia RR.

锰可通过木质化作用或直接抑制作用，与植物的真菌抗性相关联。本研究旨在评估叶面喷施锰肥对常规大豆品种及其抗草甘膦转基因衍生品种（RR）所结大豆种子的真菌侵染率，以及种子锰含量与种皮木质素水平的影响。
试验于巴西米纳斯吉拉斯州拉夫拉斯联邦大学开展，采用4×4×2因子试验方案的随机区组设计（randomized block design），设置3次重复。试验包含4个大豆品种（2个常规品种及其对应的RR衍生品种：BRS Celeste与BRS Baliza RR、BRSGO Jataí与BRS Silvânia RR）、4个锰叶面施用量（0、200、400和600 g Mn ha⁻¹）以及2个施药时期（R1期与R3期）。
分别在贮藏前及贮藏6个月后，对种子进行种子健康检测（Blotter test，吸水纸法），同时测定种子中的锰含量与种皮木质素水平。
研究发现，叶面喷施锰肥可降低所产大豆种子中菊池尾孢菌（Cercospora kikuchii）、镰孢菌属（Fusarium spp.）与曲霉属（Aspergillus spp.）的侵染率。在R1期或R3期对大豆进行叶面施锰，均可将锰转运至种子中，但不会影响种皮的木质素合成。相较于其抗草甘膦转基因衍生品种Baliza RR与Silvânia RR，常规品种Celeste与Jataí的种皮木质素水平更低。