播种深度对花生生育进程和叶片衰老的影响及其生理机制

在春播、土壤水分适宜以及起垄覆膜种植模式条件下,选用大花生品种山花108,设置3、5、7、9、11、13和15 cm (SD3、SD5、SD7、SD9、SD11、SD13和SD15) 7种播种深度,研究播种深度对花生生育进程、叶绿素含量、光合性能、干物质积累量、抗氧化酶活性及产量形成的影响。2年结果表明,播种深度明显影响花生出苗时间,与SD5处理相比, SD15处理的出苗期推迟5 d,产量形成期缩短2.5 d。播深过浅(3 cm)或过深(7 cm)显著降低了植株主茎高和侧枝长,导致叶面积指数(LAI)显著降低;且降低了产量形成期叶片叶绿素含量和光合速率,导致植株干物质积累量显著降低。播种过深(7cm)显著降低了产量形成期叶片可溶性蛋白含量和超氧化物歧化酶(SOD)及过氧化物酶(POD)活性,丙二醛(MDA)含量显著提高,导致叶片膜脂过氧化加剧。各播深处理相比,SD5处理的荚果和籽仁产量较高,主要是由于其单株结果数、单果重及出仁率的提高,播种深度超过7 cm后,减产显著。因而,春花生适宜的播种深度应控制在5 cm。

Effects and physiological mechanisms of sowing depth on the growth progress and leaf senescence of peanut

A 2-year field study was conducted using Shanhua 108 with seven levels of sowing depth (SD3, SD5, SD7, SD9, SD11, SD13, and SD15) by ridging and mulching under the suitable soil moisture condition to identify and assess the effects of sowing depth on growth progress, chlorophyll content, photosynthetic characteristics, dry matter accumulation, antioxidant enzyme activities and yield formation in peanut. The sowing depth significantly affected the emergence time of peanut. Compared with SD5 treatment, the seedling emergence time of SD15 was delayed five days (d), and the yield formation period was shortened 2.5 d. The shallow seeding treatment (SD3) and deep-planting treatments (depth ＞7 cm) significantly reduced the height of main stem and the length of branch, resulting in a decrease in leaf area index (LAI). Moreover, the chlorophyll content and net photosynthetic rate during yield formation period of those treatments were significantly decreased, leading to a decrease of dry matter accumulation of plants. At the same time, increasing sowing depth significantly reduced soluble protein content, superoxide dismutase (SOD) and peroxidase (POD) activities, increased malonaldehyde (MDA) content during the yield formation period. The pod yield and seed yield in SD5 treatment was the highest due to the highest pod number per plant, the single pod weight and shelling rate, and deep-sowing (depth >7 cm) was adverse to yield. Therefore, the appropriate sowing depth should be 5 cm in the peanut cultivation practice.