Sohail Muhammad N, Blomstedt Cecilia K, Gleadow Roslyn M
School of Biological Sciences, Monash University, Wellington Rd, Clayton, VIC 3800, Australia.
School of Life and Environmental Sciences, University of Sydney, Brownlow Hill, NSW 2570, Australia.
Plants (Basel). 2020 Dec 17;9(12):1791. doi: 10.3390/plants9121791.
In plants, the production of secondary metabolites is considered to be at the expense of primary growth. Sorghum produces a cyanogenic glycoside (dhurrin) that is believed to act as its chemical defence. Studies have shown that acyanogenic plants are smaller in size compared to the wildtype. This study aimed to investigate whether the small plant size is due to delayed germination or due to the lack of dhurrin derived nitrogen. A novel plant system consisting of () and () mutant lines was employed. The data for germination, plant height and developmental stage during seedling development and final plant reproductive fitness was recorded. The possible role of phytohormones in recovering the wildtype phenotype, especially in developmentally acyanogenic line, was also investigated. The data on plant growth have shown that the lack of dhurrin is disadvantageous to growth, but only at the early developmental stage. The plants also took longer to mature probably due to delayed flowering. None of the tested hormones were able to recover the wildtype phenotype. We conclude that the generation of dhurrin is advantageous for plant growth, especially at critical growth stages like germinating seed by providing a ready source of reduced nitrogen.
在植物中，次生代谢产物的产生被认为是以初级生长为代价的。高粱会产生一种生氰糖苷（蜀黍氰苷），据信它起到化学防御的作用。研究表明，与野生型相比，无氰植物的体型较小。本研究旨在调查植株体型较小是由于发芽延迟还是由于缺乏蜀黍氰苷衍生的氮。采用了由（）和（）突变系组成的新型植物系统。记录了种子萌发、幼苗发育期间的株高和发育阶段以及最终植株繁殖适合度的数据。还研究了植物激素在恢复野生型表型方面的可能作用，特别是在发育上无氰的品系中。关于植物生长的数据表明，缺乏蜀黍氰苷对生长不利，但仅在发育早期如此。（）植株成熟也可能由于开花延迟而花费更长时间。所测试的激素均无法恢复野生型表型。我们得出结论，蜀黍氰苷的产生对植物生长有利，特别是在关键生长阶段，如通过提供现成的还原氮源使种子萌发时。
