一种快速、受控环境下的小麦幼苗根系筛选方法与两个田间地点的营养生长阶段而非生殖生长阶段的根系深度相关性较好。
A rapid, controlled-environment seedling root screen for wheat correlates well with rooting depths at vegetative, but not reproductive, stages at two field sites.
机构信息
CSIRO Plant Industry, Canberra, ACT, Australia.
出版信息
Ann Bot. 2013 Jul;112(2):447-55. doi: 10.1093/aob/mct122.
BACKGROUND AND AIMS
Root length and depth determine capture of water and nutrients by plants, and are targets for crop improvement. Here we assess a controlled-environment wheat seedling screen to determine speed, repeatability and relatedness to performance of young and adult plants in the field.
METHODS
Recombinant inbred lines (RILs) and diverse genotypes were grown in rolled, moist germination paper in growth cabinets, and primary root number and length were measured when leaf 1 or 2 were fully expanded. For comparison, plants were grown in the field and root systems were harvested at the two-leaf stage with either a shovel or a soil core. From about the four-leaf stage, roots were extracted with a steel coring tube only, placed directly over the plant and pushed to the required depth with a hydraulic ram attached to a tractor.
KEY RESULTS
In growth cabinets, repeatability was greatest (r = 0.8, P < 0.01) when the paper was maintained moist and seed weight, pathogens and germination times were controlled. Scanned total root length (slow) was strongly correlated (r = 0.7, P < 0.01) with length of the two longest seminal axile roots measured with a ruler (fast), such that 100-200 genotypes were measured per day. Correlation to field-grown roots at two sites at two leaves was positive and significant within the RILs and cultivars (r = 0.6, P = 0.01), and at one of the two sites at the five-leaf stage within the RILs (r = 0.8, P = 0.05). Measurements made in the field with a shovel or extracted soil cores were fast (5 min per core) and had significant positive correlations to scanner measurements after root washing and cleaning (>2 h per core). Field measurements at two- and five-leaf stages did not correlate with root depth at flowering.
CONCLUSIONS
The seedling screen was fast, repeatable and reliable for selecting lines with greater total root length in the young vegetative phase in the field. Lack of significant correlation with reproductive stage root system depth at the field sites used in this study reflected factors not captured in the screen such as time, soil properties, climate variation and plant phenology.
背景和目的
根长和根深决定了植物对水分和养分的吸收，是作物改良的目标。本研究评估了一个受控环境下的小麦幼苗筛选方法，以确定其在叶片 1 或 2 完全展开时测量幼苗的根长和根数量的速度、重复性及其与田间生长的年轻和成年植株性能的相关性。
方法
重组自交系（RILs）和不同基因型在滚动湿润的发芽纸上生长在生长箱中，当第 1 或第 2 片叶子完全展开时测量初级根的数量和长度。为了比较，在田间生长的植株在两叶期用铲子或土壤芯收获根系。大约从四叶期开始，仅用钢芯管提取根系，直接放在植株上方，并通过连接在拖拉机上的液压千斤顶将其推到所需的深度。
主要结果
在生长箱中，当保持湿润并控制种子重量、病原体和发芽时间时，重复性最高（r = 0.8，P < 0.01）。扫描的总根长（慢）与用尺子测量的两条最长的轴生根长度（快）呈强相关性（r = 0.7，P < 0.01），因此每天可测量 100-200 种基因型。在两个地点的两个叶片阶段，RILs 和品种之间的田间生长根系之间存在正相关且显著（r = 0.6，P = 0.01），在两个地点的五叶期的 RILs 之间存在正相关且显著（r = 0.8，P = 0.05）。在田间用铲子或提取的土壤芯进行的测量速度很快（每个芯 5 分钟），在根冲洗和清洁后（每个芯超过 2 小时）与扫描仪测量结果具有显著正相关。在两个和五个叶片阶段的田间测量结果与开花期根系深度没有相关性。
结论
该幼苗筛选方法快速、可重复且可靠，可用于在田间幼龄期选择具有更大总根长的植株。本研究中使用的田间地点在繁殖阶段根系深度方面缺乏显著相关性，这反映了在筛选中未捕获的因素，例如时间、土壤特性、气候变异性和植物物候。
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