Rakocevic Miroslava, Maia Aline de Holanda Nunes, de Liz Marcus Vinicius, Imoski Rafaela, Helm Cristiane Vieira, Cardozo Junior Euclides Lara, Wendling Ivar
Department of Research and Development, Embrapa Florestas, Colombo 83411-000, PR, Brazil.
Statistical Research Group, Embrapa Meio Ambiente, Jaguariúna 13918-110, SP, Brazil.
Plants (Basel). 2023 Jun 2;12(11):2199. doi: 10.3390/plants12112199.
The yerba mate leaf metabolic composition depends mainly on genetics, sex, plant and leaf age, light intensity, harvest time, climate, and fertilization. In yerba mate, the secondary sexual dimorphism (SSD), the leaf metabolic SSD association with the frequency of leaf harvests, and the stability of the metabolites in the two genders over the years is not known. It was hypothesized that (1) the SSD in the metabolite segregation would differ among the winter and summer growth pauses, (2) females would show lower metabolite concentrations, and (3) the metabolic concentrations would show stability over the years on the same plants, not obligatorily associated with the SSD stability expression. Variations in theobromine, caffeine, chlorogenic and caffeic acids were correlated to the increasing time since the previous harvest, especially in females. However, the frequency of the metabolic SSD were associated with the studied growth pauses, rejecting the first hypothesis. No regular gender superiority was expressed in the yerba mate leaf secondary metabolites, rejecting our second hypothesis, even though more cases of superior female metabolite accumulation were identified. The stability of the leaf protein was preserved over the four years, with no SSD cases observed. The leaf methylxanthines were time stable, while the decrease in the phenolic content occurred with tree aging, which was not associated with the SSD expression, partially proving our third hypothesis. The novelty was related to the time stability of the leaf metabolic SSD observed over the winter and summer growth pauses, and over the four consecutive years without a regular expression of the male- or female-biased concentrations in the studied metabolites. To demystify the random metabolic gender responses in yerba mate, gender-orientated experiments with a high number of tree repetitions must be conducted, including clonal plants grown in various environments, such as monoculture and agroforestry, or on plantations in different climates and altitudes.
马黛茶树叶的代谢成分主要取决于遗传因素、性别、植株和叶片年龄、光照强度、收获时间、气候以及施肥情况。在马黛茶中，其次生性二态性（SSD）、叶片代谢的SSD与叶片收获频率的关联以及多年来两种性别的代谢产物稳定性尚不清楚。研究假设如下：（1）代谢物分离中的SSD在冬季和夏季生长停滞期会有所不同；（2）雌性的代谢物浓度会较低；（3）同一植株上的代谢物浓度多年来会保持稳定，不一定与SSD稳定性表达相关。可可碱、咖啡因、绿原酸和咖啡酸的变化与上次收获后的时间增加相关，尤其是在雌性植株中。然而，代谢SSD的频率与所研究的生长停滞期相关，这否定了第一个假设。在马黛茶树叶次生代谢产物中未表现出常规的性别优势，这否定了我们的第二个假设，尽管发现了更多雌性代谢物积累优势的情况。叶片蛋白质在四年中保持稳定，未观察到SSD情况。叶片甲基黄嘌呤在时间上是稳定的，而酚类含量随树木老化而降低，这与SSD表达无关，部分证明了我们的第三个假设。这项研究的新颖之处在于观察到在冬季和夏季生长停滞期以及连续四年中，马黛茶树叶代谢SSD在时间上的稳定性，且所研究的代谢物中未定期出现偏向雄性或雌性的浓度表达。为了解开马黛茶中随机的代谢性别反应之谜，必须进行大量树木重复的性别定向实验，包括在各种环境中种植的克隆植物，如单一栽培和农林业环境，或在不同气候和海拔的种植园中。
