Mandizvo T, Odindo A O
Crop Science, School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa.
Heliyon. 2019 Feb 19;5(2):e01249. doi: 10.1016/j.heliyon.2019.e01249. eCollection 2019 Feb.
Bambara groundnut is cultivated using landraces of different seed coat colours. However, very few studies have associated the seed coat colour (morphological feature) with other physiological and biochemical processes as underlying the observed differences in seed quality among landraces. This research sought to investigate seed quality characteristics (viability and vigour) of landraces on the basis of seed coat colour with the hypothesis that; seed coat colour could be linked to other properties (physical, physiological, biochemical and ultra-structure) that may account for seed quality with respect to germination, vigour and storage potential. Four landraces were analysed for differences in seed coat colour and seed coat thickness using a scanning electron microscope (SEM). Seed imbibition, electrolyte conductivity, tetrazolium test, and standard germination tests were combined to evaluate the viability of seeds after deterioration through accelerated ageing (AA) at 42 °C and 100% relative humidity (RH) over 5 durations, namely 24, 48, 72, 96 and 120 hours. There were significant differences (P < 0.001) among landraces with respect to seed coat colour, seed coat thickness, electrical conductivity (EC), hydration rate, germination rate and length of the measured seedling axis. The light coloured landrace, Kazai, had the highest germination (66.9%) whereas the dark coloured landrace, G340A, had the lowest final germination (53.6%) after 120 hours of seed ageing. Likewise, G340A and Kazai had the highest (110.33 μS cm g) and lowest EC (92 μS cm g), respectively. Electron microscope revealed that dark and light seeds had the thickest (127 μm) and the thinnest (104.6 μm) seed coats, repsectively. This study highlighted that (1) seed coat thickness and colour alone do not account for hydration pattern of Bambara groundnut landraces and (2) Bambara groundnut seeds viability may not necessarily imply good seed vigour.
班巴拉花生是利用不同种皮颜色的地方品种进行种植的。然而，很少有研究将种皮颜色（形态特征）与其他生理和生化过程联系起来，这些过程是地方品种间种子质量差异的潜在原因。本研究旨在基于种皮颜色调查地方品种的种子质量特征（活力和 vigor），并提出假设：种皮颜色可能与其他特性（物理、生理、生化和超微结构）相关，这些特性可能解释种子在发芽、活力和储存潜力方面的质量。使用扫描电子显微镜（SEM）分析了四个地方品种的种皮颜色和种皮厚度差异。通过种子吸收、电解质电导率、四唑试验和标准发芽试验，结合在42℃和100%相对湿度（RH）下加速老化（AA）5个时间段（即24、48、72、96和120小时）后种子的活力进行评估。在种皮颜色、种皮厚度、电导率（EC）、水合速率、发芽率和测量的幼苗轴长度方面，地方品种之间存在显著差异（P < 0.001）。浅色地方品种Kazai的发芽率最高（66.9%），而深色地方品种G340A在种子老化120小时后的最终发芽率最低（53.6%）。同样，G340A和Kazai的EC分别最高（110.33 μS cm g）和最低（92 μS cm g）。电子显微镜显示，深色和浅色种子的种皮分别最厚（127 μm）和最薄（104.6 μm）。本研究强调：（1）仅种皮厚度和颜色不能解释班巴拉花生地方品种的水合模式；（2）班巴拉花生种子的活力不一定意味着良好的种子 vigor。
