Variability of leaves of Betula pendula Roth during the growing season in the recreation area in the industrial center

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Introduction The features of leaf growth [1] during the growing season are not well understood. Peculiarities of morphological changes in leaves during the growing season should be taken into account when organizing monitoring studies [2]. In assessing the resistance of plants, depending on the conditions of their growth, the method of assessing the development stability and asymmetry is used [3-10]. The aim of the work was to study the morphological changes in Betula pendula Roth leaves under environmental pollution. The subject of the research is Betula pendula plantations. Materials and methods The studies were conducted in the recreation area on the territory of the Ufa Industrial Center. A general description of the stands has been presented previously [2]. Objects of study - model trees Betula pendula Roth. One tree is large-leaved, the other is small-leaved. In the crown of each tree, 10 leaves are numbered. Each leaf was photographed during the growing season (June - September). In August, reconstruction activities were carried out in the park. Small-leaved tree was cut down. Therefore, data on small-leaved tree are presented for June, July and August. Used a Nikon D40 digital camera. Photographs of the leaves were computer processed using standard programs. A method was used to study the morphological characters of leaves [11; 12]. The stability of the development of leaves of tree stands is estimated. The studies were carried out in 2019, which was characterized by average values of weather and climatic conditions. The actual material for assessing the stability of development of birch leaves is the morphological characteristics of the right and left halves of the leaf according to 5 signs [13]: 1) the width of the left and right halves of the sheet; 2) the length of the vein of the second order from the base of the leaf; 3) the distance between the bases of the first and second veins of the second order; 4) the distance between the ends of these veins; 5) the angle between the main vein and the second vein of the second order from the base of the sheet. Statistical processing of the research results was carried out in the programs: STATISTICA, GraphPad Prism, Microsoft Excel. Results Shown are changes in birch leaves during the growing season [14]. The integral indicator of the stability of leaf development (small-leaved tree and large-leaved tree) was calculated according to five criteria [15] (Figures 1-5). The obtained data were statistically processed, 1-way ANOVA, ANOVA (Tables 1-15). a b Figure 1. Integral index of stability of leaf development (the 1st sign): а - large-leaved tree; b - small-leaved tree Table 1 Column statistics (the 1st sign) Month June July August September Тree Large-leaved Small-leaved Large-leaved Small-leaved Large-leaved Small-leaved Large-leaved Small-leaved Number of values 9 8 9 8 9 8 9 - Minimum 0.005 0.012 0.003 0.011 0.006 0.011 0.009 - Maximum 0.132 0.117 0.061 0.092 0.080 0.154 0.116 - Mean 0.063 0.042 0.032 0.034 0.038 0.061 0.056 - Std. Deviation 0.043 0.034 0.024 0.026 0.029 0.060 0.036 - Std. Error 0.014 0.012 0.008 0.009 0.010 0.021 0.012 - Lower 95% CI of mean 0.030 0.014 0.014 0.013 0.016 0.011 0.029 - Upper 95% CI of mean 0.096 0.071 0.050 0.055 0.060 0.111 0.083 - Coefficient of variation 68.28% 80.93% 74.00% 75.48% 75.69% 98.86% 63.48% - Sum 0.569 0.338 0.289 0.272 0.340 0.488 0.505 - Table 2 1-way ANOVA (the 1st sign) Parameter Value Large-leaved tree Small-leaved tree P value 0.180 0.445 P value summary ns ns Are means signif. different? (P < 0,05) No No Number of groups 4 3 F 1.735 0.841 R squared 0.140 0.074 Table 3 ANOVA (the 1st sign) ANOVA Table SS df MS Large-leaved tree Treatment (between columns) 0.00587 3 0.00196 Residual (within columns) 0.03611 32 0.00113 Total 0.04199 35 Small-leaved tree Treatment (between columns) 0.00306 2 0.00153 Residual (within columns) 0.03825 21 0.00182 Total 0.04131 23 a b Figure 2. Integral index of stability of leaf development (the 2nd sign): a - large-leaved tree; b - small-leaved tree Table 4 Column statistics (the 2nd sign) Month June July August September Тree Large-leaved Small-leaved Large-leaved Small-leaved Large-leaved Small-leaved Large-leaved Small-leaved Number of values 9 8 9 8 9 8 9 - Minimum 0.001 0.007 0.005 0.004 0.003 0.001 0.002 - Maximum 0.033 0.039 0.088 0.041 0.030 0.051 0.039 - Mean 0.016 0.022 0.028 0.021 0.013 0.016 0.017 - Std. Deviation 0.012 0.012 0.025 0.011 0.009 0.018 0.013 - Std. Error 0.004 0.004 0.008 0.004 0.003 0.007 0.004 - Lower 95% CI of mean 0.007 0.012 0.009 0.012 0.006 0.000 0.007 - Upper 95% CI of mean 0.025 0.033 0.047 0.030 0.019 0.031 0.027 - Coefficient of variation 75.32% 55.30% 90.32% 50.51% 69.22% 117.91% 78.57% - Sum 0.140 0.179 0.252 0.171 0.113 0.125 0.150 - Table 5 1-way ANOVA (the 2nd sign) Parameter Value Large-leaved tree Small-leaved tree P value 0.207 0.600 P value summary ns ns Are means signif. different? (P < 0,05) No No Number of groups 4 3 F 1.609 0.523 R squared 0.131 0.047 Table 6 ANOVA (the 2nd sign) ANOVA Table SS df MS Large-leaved tree Treatment (between columns) 0.00124 3 0.00041 Residual (within columns) 0.00819 32 0.00026 Total 0.00943 35 Small-leaved tree Treatment (between columns) 0.00021 2 0.00011 Residual (within columns) 0.00426 21 0.00020 Total 0.00448 23 1st sign - the width of the left and right halves of the leaf. Bartlett’s test for equal variances. Large-leaved tree: bartlett’s statistic (corrected) 3.014; P value 0.389; P value summary “ns”; Do the variances differ signif. (P < 0.05) - “No”. Small-leaved tree: bartlett’s statistic (corrected) 5.063; P value 0.080; P value summary “ns”; Do the variances differ signif. (P < 0.05) - “No”. 2nd sign - the length of the vein of the second order from the base of the leaf. Bartlett’s test for equal variances. Large-leaved tree: bartlett’s statistic (corrected) 10.1; P value 0.018; P value summary “ns”; Do the variances differ signif. (P < 0.05) - “Yes”. Small-leaved tree: bartlett’s statistic (corrected) 2.128; P value 0.345; P value summary “ns”; Do the variances differ signif. (P < 0.05) - “No”. 3rd sign - the distance between the bases of the first and second veins of the second order of the leaf. Bartlett’s test for equal variances. Large-leaved tree: bartlett’s statistic (corrected) 1.746; P value 0.627; P value summary “ns”; Do the variances differ signif. (P < 0.05) - “No”. Small-leaved tree: bartlett’s statistic (corrected) 0.086; P value 0.958; P value summary “ns”; Do the variances differ signif. (P < 0.05) - “No”. 4th sign - the distance between the ends of the first and second veins of the second order of the leaf. Bartlett’s test for equal variances. Large-leaved tree: bartlett’s statistic (corrected) 2.054; P value 0.561; P value summary “ns”; Do the variances differ signif. (P < 0.05) - “No”. Small-leaved tree: bartlett’s statistic (corrected) 0.158; P value 0.924; P value summary “ns”; Do the variances differ signif. (P < 0.05) - “No”. 5th sign - the angle between the main vein and the second vein of the second order from the base of the leaf. Bartlett’s test for equal variances. Large-leaved tree: bartlett’s statistic (corrected) 0.808; P value 0.848; P value summary “ns”; Do the variances differ signif. (P < 0.05) - “No”. Small-leaved tree: bartlett’s statistic (corrected) 2.52; P value 0.284; P value summary “ns”; Do the variances differ signif. (P < 0.05) - “No”. а b Figure 3. Integral index of stability of leaf development (the 3rd sign): а - large-leaved tree; b - small-leaved tree Table 7 Column statistics (the 3rd feature) Month June July August September Тree Large-leaved Small-leaved Large-leaved Small-leaved Large-leaved Small-leaved Large-leaved Small-leaved Number of values 9 8 9 8 9 8 9 - Minimum 0.008 0.036 0.017 0.008 0.016 0.014 0.010 - Maximum 0.130 0.214 0.101 0.188 0.127 0.195 0.128 - Mean 0.060 0.106 0.052 0.064 0.068 0.060 0.070 - Std. Deviation 0.039 0.068 0.029 0.064 0.035 0.060 0.046 - Std. Error 0.013 0.024 0.010 0.022 0.012 0.021 0.015 - Lower 95% CI of mean 0.030 0.049 0.030 0.011 0.041 0.010 0.034 - Upper 95% CI of mean 0.090 0.162 0.074 0.117 0.095 0.111 0.105 - Coefficient of variation 64.24% 63.97% 55.21% 99.23% 51.41% 99.83% 66.29% - Sum 0.541 0.845 0.470 0.512 0.612 0.483 0.628 - Table 8 1-way ANOVA (the 3rd feature) Parameter Value Large-leaved tree Small-leaved tree P value 0.746 0.310 P value summary ns ns Are means signif. different? (P < 0.05) No No Number of groups 4 3 F 0.411 1.241 R squared 0.037 0.106 Table 9 ANOVA (the 3rd feature) ANOVA Table SS df MS Large-leaved tree Treatment (between columns) 0.00175 3 0.00058 Residual (within columns) 0.04547 32 0.00142 Total 0.04722 35 Small-leaved tree Treatment (between columns) 0.01012 2 0.00506 Residual (within columns) 0.08562 21 0.00408 Total 0.09573 23 а b Figure 4. Integral index of stability of leaf development (the 4th sign): а - large-leaved tree; b - small-leaved tree Table 10 Column statistics (the 4th sign) Month June July August September Тree Large-leaved Small-leaved Large-leaved Small-leaved Large-leaved Small-leaved Large-leaved Small-leaved Number of values 9 8 9 8 9 8 9 - Minimum 0.022 0.010 0.007 0.022 0.016 0.010 0.004 - Maximum 0.136 0.175 0.086 0.171 0.119 0.175 0.099 - Mean 0.083 0.072 0.056 0.062 0.065 0.060 0.061 - Std. Deviation 0.041 0.059 0.027 0.052 0.034 0.060 0.026 - Std. Error 0.014 0.021 0.009 0.018 0.011 0.021 0.009 - Lower 95% CI of mean 0.051 0.022 0.036 0.018 0.039 0.010 0.041 - Upper 95% CI of mean 0.115 0.121 0.077 0.105 0.091 0.110 0.081 - Coefficient of variation 49.68% 82.85% 48.02% 83.99% 52.01% 99.89% 43.46% - Sum 0.748 0.574 0.508 0.495 0.582 0.478 0.548 - Table 11 1-way ANOVA (the 4th sign) Parameter Value Large-leaved tree Small-leaved tree P value 0.341 0.905 P value summary ns ns Are means signif. different? (P < 0,05) No No Number of groups 4 3 F 1.157 0.101 R squared 0.098 0.009 Table 12 ANOVA (the 4th sign) ANOVA Table SS df MS Large-leaved tree Treatment (between columns) 0.00371 3 0.00124 Residual (within columns) 0.03417 32 0.00107 Total 0.03787 35 Small-leaved tree Treatment (between columns) 0.00066 2 0.00033 Residual (within columns) 0.06858 21 0.00327 Total 0.06923 23 а b Figure 5. Integral index of stability of leaf development (the 5th sign): а - large-leaved tree; b - small-leaved tree Table 13 Column statistics (the 5th feature) Month June July August September Тree Large-leaved Small-leaved Large-leaved Small-leaved Large-leaved Small-leaved Large-leaved Small-leaved Number of values 9 8 9 8 9 8 9 - Minimum 0.015 0.014 0.005 0.001 0.015 0.003 0.010 - Maximum 0.150 0.193 0.129 0.113 0.158 0.085 0.119 - Mean 0.052 0.049 0.050 0.035 0.046 0.035 0.039 - Std. Deviation 0.041 0.059 0.046 0.040 0.046 0.032 0.034 - Std. Error 0.014 0.021 0.015 0.014 0.015 0.011 0.011 - Lower 95% CI of mean 0.020 0.000 0.014 0.002 0.011 0.008 0.012 - Upper 95% CI of mean 0.084 0.098 0.085 0.068 0.081 0.062 0.065 - Coefficient of variation 79.04% 119.82% 93.14% 113.74% 99.09% 92.32% 88.61% - Sum 0.470 0.393 0.447 0.278 0.415 0.280 0.349 - Table 14 1-way ANOVA (the 5th feature) Parameter Value Large-leaved tree Small-leaved tree P value 0.914 0.768 P value summary ns ns Are means signif. different? (P < 0,05) No No Number of groups 4 3 F 0.173 0.268 R squared 0.016 0.025 Table 15 ANOVA (the 5th feature) ANOVA Table SS df MS Large-leaved tree Treatment (between columns) 0.00092 3 0.00031 Residual (within columns) 0.05690 32 0.00178 Total 0.05780 35 Small-leaved tree Treatment (between columns) 0.00108 2 0.00054 Residual (within columns) 0.04250 21 0.00202 Total 0.04358 23 Discussion ANOVA analysis of variance showed that there are no differences between the average values of the compared groups on five grounds. Using the Bartlett test, an approximate criterion was determined to assess the uniformity of variance for equal deviations on five grounds. To the question whether these deviations differ significantly between large leaves (according to the first, third, fourth and fifth characteristics), the answer is received - there are no differences. According to the second criterion (the length of the vein of the second order from the base of the leaf), these deviations differ. To the question whether these deviations differ significantly in small leaves, the answer is received - there are no differences. The formation of an individual development trajectory occurs at each leaf. This can be seen in the figures presented. It is associated with growing conditions - a recreation area in an industrial center with a high recreational load. Under extreme growing conditions, an adaptive reaction of the leaves is manifested. The phenomenon of adaptive polymorphism was noted in birch leaves. However, the morphological and functional features of the leaf are inextricably linked. Conclusion During the growing season on the territory of the recreation zone in the Ufa industrial center, deviations in the development of Betula pendula leaves were noted. It was noted that leaf asymmetry indices can be used to characterize the state of Betula pendula trees. The need to monitor the state of the stands, as well as the timely detection of violations and changes in the condition of individual trees, is associated with the development of measures for the care of the stands and for the reconstruction of the stands.

About the authors

Olesya V. Tagirova

Bashkir State Pedagogical University named after M. Akmulla

Author for correspondence.
Email: olecyi@mail.ru
ORCID iD: 0000-0003-1615-7005

Candidate of Biological Sciences, Associate Professor, Associate Professor of the Department of Ecology, Geography and Nature Management

3A Oktyabr'skoi Revolyutsii St, Ufa, 450008, Russian Federation

Alexsei Yu. Kulagin

Ufa Federal Research Center of the Russian Academy of Sciences

Email: coolagin@list.ru
ORCID iD: 0000-0002-6617-1027

Doctor of Biological Sciences, Professor, Head of the Forestry Laboratory

69 Prospekt Oktyabrya, Ufa, 450054, Russian Federation

References