Danziger Nadav, Bernstein Nirit
Institute of Soil Water and Environmental Sciences, Volcani Center, 68 HaMaccabim Road, P.O. Box 15159, Rishon LeZion 7505101, Israel.
Plants (Basel). 2021 Sep 3;10(9):1834. doi: 10.3390/plants10091834.
Since plant organs sense their environment locally, gradients of micro-climates in the plant shoot may induce spatial variability in the physiological state of the plant tissue and hence secondary metabolism. Therefore, plant architecture, which affects micro-climate in the shoot, may considerably affect the uniformity of cannabinoids in the plant, which has significant pharmaceutical and economic importance. Variability of micro-climates in plant shoots intensifies with the increase in plant size, largely due to an increase in inter-shoot shading. In this study, we therefore focused on the interplay between shoot architecture and the cannabinoid profile in large cannabis plants, ~2.5 m in height, with the goal to harness architecture modulation for the standardization of cannabinoid concentrations in large plants. We hypothesized that (i) a gradient of light intensity along the plants is accompanied by changes to the cannabinoid profile, and (ii) manipulations of plant architecture that increase light penetration to the plant increase cannabinoid uniformity and yield biomass. To test these hypotheses, we investigated effects of eight plant architecture manipulation treatments involving branch removals, defoliation, and pruning on plant morpho-physiology, inflorescence yield, cannabinoid profile, and uniformity. The results revealed that low cannabinoid concentrations in inflorescences at the bottom of the plants correlate with low light penetration, and that increasing light penetration by defoliation or removal of bottom branches and leaves increases cannabinoid concentrations locally and thereby through spatial uniformity, thus supporting the hypotheses. Taken together, the results reveal that shoot architectural modulation can be utilized to increase cannabinoid standardization in large cannabis plants, and that the cannabinoid profile in an inflorescence is an outcome of exogenous and endogenous factors.
由于植物器官在局部感知其环境，植物地上部分微气候的梯度可能会诱导植物组织生理状态的空间变异性，进而影响次生代谢。因此，影响地上部分微气候的植物结构可能会极大地影响植物中大麻素的均匀性，这具有重要的药学和经济意义。随着植物大小的增加，植物地上部分微气候的变异性会加剧，这主要是由于茎间遮荫增加所致。因此，在本研究中，我们聚焦于大型大麻植株（高度约2.5米）的茎结构与大麻素谱之间的相互作用，目的是利用结构调控来使大型植株中大麻素浓度标准化。我们假设：（i）沿植株的光照强度梯度伴随着大麻素谱的变化；（ii）对植物结构进行操作以增加光线穿透植株的程度，可提高大麻素的均匀性并增加生物量产量。为了验证这些假设，我们研究了涉及去除枝条、落叶和修剪的八种植物结构操作处理对植物形态生理学、花序产量、大麻素谱和均匀性的影响。结果表明，植株底部花序中大麻素浓度较低与光线穿透率低有关，通过落叶或去除底部枝条和叶片增加光线穿透率，可局部增加大麻素浓度，从而通过空间均匀性实现这一点，从而支持了这些假设。综上所述，结果表明茎结构调控可用于提高大型大麻植株中大麻素的标准化程度，并且花序中的大麻素谱是外源和内源因素共同作用的结果。
