School of Biology, Faculty of Biological Sciences, University of Leeds, Leeds, UK.
Plant Cell Environ. 2021 Apr;44(4):1202-1214. doi: 10.1111/pce.13984. Epub 2020 Dec 28.
Plants must carefully coordinate their growth and development with respect to prevailing environmental conditions. To do this, plants can use a range of nutritional and non-nutritional information that allows them to proactively modulate their growth to avoid resource limitations. As is well-known to gardeners and horticulturists alike, substrate volume strongly influences plant growth, and maybe a key source of non-nutritional information for plants. However, the mechanisms by which these substrate volume effects occur remain unclear. Here, we show that wheat plants proactively modulate their shoot growth with respect to substrate volume, independent of nutrient availability. We show that these effects occur in two phases; in the first phase, the dilution of a mobile 'substrate volume-sensing signal' (SVS) allows plants to match their shoot (but not root) growth to the total size of the substrate, irrespective of how much of this they can occupy with their roots. In the second phase, the dilution of a less mobile 'root density-sensing signal' (RDS) allows plants to match root growth to actual rooting volume, with corresponding effects on shoot growth. We show that the effects of soil volume and plant density are largely interchangeable and that plants may use both SVS and RDS to detect their neighbours and to integrate growth responses to both volume and the presence of neighbours. Our work demonstrates the remarkable ability of plants to make proactive decisions about their growth, and has implications for mitigating the effects of dense sowing of crops in agricultural practice.
植物必须仔细协调其生长和发育与流行的环境条件。为此，植物可以使用一系列营养和非营养信息，使它们能够主动调节生长，以避免资源限制。正如园丁和园艺家都知道的那样，基质体积强烈影响植物生长，也许是植物非营养信息的一个关键来源。然而，这些基质体积效应发生的机制仍不清楚。在这里，我们表明，小麦植物主动调节其相对于基质体积的芽生长，而与养分供应无关。我们表明，这些效应发生在两个阶段；在第一阶段，移动的“基质体积感应信号”（SVS）的稀释允许植物将其芽（但不是根）生长与基质的总大小相匹配，而不管它们的根可以占据多少。在第二阶段，较少移动的“根密度感应信号”（RDS）的稀释允许植物将根生长与实际生根体积相匹配，对芽生长产生相应的影响。我们表明，土壤体积和植物密度的影响在很大程度上是可互换的，植物可能会同时使用 SVS 和 RDS 来检测它们的邻居，并整合对体积和邻居存在的生长反应。我们的工作展示了植物在生长决策方面的惊人能力，并对减轻农业实践中作物密集播种的影响具有重要意义。
