Photochemistry differs between male and female Juniperus communis L. independently of nutritional availability

Abstract

Key message Juniperus communis males are better adapted than females to changing, seasonal environmental conditions due to their higher photosynthetic capacity and the higher concentration of photosynthetic pigments in their needles. Males cope with ROS more efficiently than females having greater carotenoids concentration in needles. Abstract In dioecious woody plants, females often exhibit greater reproductive effort than male plants and as a result, they can be more vulnerable to different stressors. We hypothesized that female plants of J. communis L. could have a lower photochemical capacity and a higher level of antioxidant enzyme activity and that these differences between males and females would be more pronounced under conditions where nutrient availability is limited. We also assume that additional stressors connected with different seasons would increase those differences. Male and female plants of J. communis growing in fertilized or non-fertilized soils were used to test this hypothesis. The effect of fertilization and sex on photochemical parameters derived from chlorophyll a fluorescence light curves, and on the concentrations of photosynthetic pigments in needles, was determined in different seasons within 2 years. To assess the tolerance of male and female plants to the nutrient deficit, antioxidant enzyme activity, and the level of reactive oxygen species (ROS) were determined. Results revealed sex-related differences in photochemical parameters, level of antioxidant enzyme activity, H2O2 levels, the concentration of photosynthetic pigments, and in the leaf mass-to-area ratio. This indicates that J. communis males could be better adapted than females to changing, seasonal environmental conditions due to their higher photosynthetic capacity, as reflected by their higher ETRmax, and a higher concentration of photosynthetic pigments in their needles. The sex-related differences concerning photosynthetic capacity and stress response found in our study are constitutive traits of each sex and are genetically based as they occurred independently of fertilization.

Sexual Dimorphism in the Chemical Composition of Male and Female in the Dioecious Tree, Juniperus communis L., Growing under Different Nutritional Conditions

“…Low concentrations of nitrogen can influence growth in female plants due to lower photosynthetic capacity [23]. In the current study, the lower levels of nitrogen detected in needles of female plants of J. communis may be connected to the lower photosynthetic efficiency of females detected in a previous study [32]. It has been previously suggested that male individuals of J. thurifera use available nutrients to increase gas exchange capacity, while females exhibit a long-term strategy and increase N storage, saving N-reserves for reproduction [53].…”

“…Notably, the highest air temperatures also occurred at this time, which may have affected starch accumulation as elevated temperature (more than 25 • C) can inhibit starch synthesis [48]. Additionally, our previous study shows that the high temperatures can also have a differential impact on leaf mass area (LMA) values in male and female plants; with females exhibiting a significantly higher LMA during the hottest month of the two years of the study (females 156.78 ± 3.13 and males 147.35 ± 3.23, p = 0.0465) [32]. The thicker lamina present in leaves of female plants, relative to male plants, can better protect cells against a sharp rise in temperature [49].…”

“…Previous studies showed that Juniperus communis is a good model species for the study of sexual dimorphism in dioecious plants. Significant differences in growth rate, morphology, and ecophysiology were found in this species [5,31,32], but no detailed analysis of chemical composition, considering both differences between sexes and soil fertilization treatment, have been conducted. Moreover, similarly to many other dioecious species, a decline in population size of J. communis and a sex ratio bias are observed [33][34][35][36] which makes such studies even more necessary.…”

Zimbro (Juniperus communis L.) as a Promising Source of Bioactive Compounds and Biomedical Activities: A Review on Recent Trends

“…Although no studies have specifically reported the chlorophyll content of J. communis L. species, Rabska and colleagues [ 56 ] analyzed their total levels in fertilized and nonfertilized in both genders of this plant in autumn and winter (species not specified). The obtained data revealed nonfertilized plants had a lower concentration of total chlorophyll content than the fertilized ones (mean values of 5.0 versus (vs.) 7.4 mg/g in autumn and 3.6 vs. 4.8 mg/g in winter, respectively), and also lower amounts of total carotenoids (mean values of 0.64 and 0.95 mg/g for female and male, respectively, in autumn, and scores of 0.87 against 1.2 mg/g in winter).…”

Seed Quantity or Quality?—Reproductive Responses of Females of Two Dioecious Woody Species to Long-Term Fertilisation

“…This suggests that, although in a rich environment, female plants invest more into production of numerous flowers, while the efficiency of seed development and seed production is related to factors other than just nutritional availability and pollen availability [ 47 ]. Moreover, our earlier studies showed that fertilised female plants of both species are characterised by higher photosynthetic activity [ 38 , 48 ] and higher biomass [ 39 ] than their non-fertilised counterparts. These observations indicate that the allocation of plant resources to seed production is a reasonable/controlled investment of resource allocation; thus, in a non-fertilised environment, when the plant has already invested part of the available resource for female reproductive structure development, the necessary resources were provided by the plant (at the cost of vegetative growth or resource allocation) to ensure development of seeds [ 47 ].…”