School of Biology and Environmental Sciences, University College Dublin, Belfield, Dublin 4, Republic of Ireland.
School of Biology and Environmental Sciences, University College Dublin, Belfield, Dublin 4, Republic of Ireland; and Corresponding author. Email:
Funct Plant Biol. 2021 Mar;48(4):448-459. doi: 10.1071/FP20287.
The root hair-less brb of Hordeum vulgare L. (bald root barley) mutant was used to assess the significance that root hairs have for the hydraulic properties of roots and response to a limited supply of mineral nutrients in plants grown on hydroponics. The barley brb mutant and its parent wild-type (H. vulgare cv. Pallas) were grown under nutrient sufficient control conditions, and under conditions of low supply of P and N. Plants were analysed when they were 14-18 days old. Root hydraulic conductivity (Lp) was determined for excised root systems and intact transpiring plants, and cell Lp was determined through cell pressure probe measurements. The formation of Casparian bands and suberin lamellae was followed through staining of cross-sections. The presence or absence of root hairs had no effect on the overall hydraulic response of plants to nutritional treatments. Root and cell Lp did not differ between the two genotypes. The most apparent difference between brb and wild-type plants was the consistently reduced formation of apoplastic barriers in brb plants. Any hydraulic function of root hairs can be redundant in barley, at least under the hydroponic conditions tested.
以大麦突变体根毛缺失型（无发根大麦）的根毛为研究对象，评估了根毛在植物根系水力性质以及在水培条件下对有限养分供应的响应中的重要性。在养分充足的控制条件下以及磷、氮供应不足的条件下，对大麦突变体 brb 及其野生型亲本（Hordeum vulgare cv. Pallas）进行了生长。当植株生长至 14-18 天时对其进行分析。通过离体根系和蒸腾植物的测定，对根系水力传导率（Lp）进行了测定，通过细胞压力探针测量，对细胞 Lp 进行了测定。通过对切片进行染色，对 Casparian 带和栓质层的形成进行了跟踪观察。根毛的有无对植物对营养处理的整体水力响应没有影响。两种基因型之间的根和细胞 Lp 没有差异。brb 植株与野生型植株之间最明显的差异是 brb 植株中质外体屏障的形成始终减少。在大麦中，根毛的任何水力功能都可能是多余的，至少在测试的水培条件下是如此。
