Associations among leaf developmental stability, canalization and phenotypic plasticity in response to population density in Abutilon theophrasti under contrasting soil conditions at different growth stages

Most studies on animals have conducted comparative studies to deduce the possible relationships among developmental stability, canalization and phenotypic plasticity, there is a lack of direct evidence in plants, which should be better study materials. To investigate the correlations among developmental stability, canalization and plasticity in plants, we conducted a field experiment with Abutilon theophrasti, by subjected plants to three densities under infertile vs. fertile soil conditions, and measured leaf size, leaf fluctuating asymmetry (FA), and calculated coefficient of variation among leaves within individuals (CVleaf) and among individuals (CVin) and relative plasticity (PIrel) and its degree in leaf size at three growth stages, to analyze the responses of their correlations to density and how they may vary with soil conditions or growth stages. Results showed a decrease of FA, CVleaf and PIrel and an increase of CVin in leaf size, with increased density. In most cases, there were no correlations among these variables, but negative correlations between CVin and PIrel, positive correlations between FA and PIrel at high density and/or in fertile soil, in infertile soil. It suggested that higher FA may indicate the state of faster growth rather than an indicator of environmental stresses; there are correlations among developmental stability, canalization and plasticity, which may be complex, affected by other factors. The loss of developmental stability may be beneficial for plant response to environmental stresses, while decreased canalization can be either disadvantageous or advantageous, depending on that the size variation results from an increase or decrease of smaller individuals, and whether its correlations with other variables reflect beneficial or adverse environmental effects.

Effects of freezing seeds Abutilon theophrasti Medik. and Eruca vesicaria (L.) Cav. for the appearance, growth and development of plants

A comparative study of the effect of different storage regimes of seeds (at + 5 ° С, -20 ° С and under deep freezing conditions at -196 ° С) of two cultivated plants of the Abutilon theophrasti Medik. and Eruca vesicaria (L.) Cav. on their viability and the development of plants from them in the field was carried out. Freezing increases the laboratory and field germination of the seeds of the A. theophrasti and does not significantly affect the germination of the seeds of the A. theophrasti, and also increases the germination energy of the seeds of both plant species. It did not cause the appearance of non-viable, ugly seedlings and plants. Plants went through a full development cycle and set full-value seeds. Biometric parameters of plants obtained from thawed seeds and control ones are very close. Cryopreservation is a promising way of storing seeds of the studied species, since it ensures longer periods of preservation of their viability. Keywords: ABUTILON THEOPHRASTI; ERUCA VESICARIA; SEED BANKS; LONG-TERM SEED STORAGE REGIMES; CRYOPRESERVATION

Survival of Xanthomonas cucurbitae in different cropping rotations, plant debris, and weeds in pumpkin fields

This study was conducted to evaluate the effectiveness of crop rotation in managing Xanthomonas cucurbitae, the causal agent of Xanthomonas leaf spot, in pumpkin fields. The study was conducted using ‘Howden’ pumpkin, a susceptible pumpkin cultivar, at four sites with no history of Xanthomonas leaf spot. All sites were planted with pumpkins in the first year of crop rotations. The disease developed at all four sites. In a three-year rotation with nonhost crops, the severity of Xanthomonas leaf spot in pumpkin plots was significantly (P<0.05) lower than those of plots in the two-year rotation with nonhost crops and continuous pumpkin production. Furthermore, X. cucurbitae was recovered from pumpkin plant debris 15 months after harvesting pumpkins in commercial fields, and the pathogen was viable. X. cucurbitae was also isolated from asymptomatic weeds in pumpkin fields. In a greenhouse inoculation of weeds with X. cucurbitae, however, Xanthomonas leaf spot developed only on leaves of bur cucumber (Sicyos angulatus) and velvetleaf (Abutilon theophrasti) weeds. In the infested soil with X. cucurbitae, the bacterium was not recovered after 15, 42, and 56 days at 22, 12, and 4℃, respectively. The results showed that crop rotation alone does not provide adequately protection of pumpkin plants against X. cucurbitae.

Morphological canalization, integration and plasticity in response to population density in Abutilon theophrasti: influences of soil conditions and growth stages

Phenotypic integration and developmental canalization have been hypothesized to constrain the degree of phenotypic plasticity, but there is little evidence for the relationships among the three processes in different environments, especially for plants under natural conditions. To address this issue, we conducted a field experiment by subjecting plants of Abutilon theophrasti to low, medium and high densities, under infertile and fertile soil conditions, measured a variety of traits and analyzed canalization (coefficient of variation [CV]), integration (coefficient of integration [CI] and the number of significant correlations of a trait with other traits [NC]), and plasticity (REL RDPIs and ABS RDPIs) in these traits and their relationships at two stages of plant growth. Our results showed an increase in mean CV, NC and ABS RDPIs of traits with density, and the positive correlations between trait NC and ABS RDPIs became stronger with higher densities but weaker over time in fertile soil, while correlations among trait CV, NC and ABS RDPIs became stronger over time in infertile soil. Results suggested shared or cooperation mechanisms among phenotypic integration, canalization and plasticity. Soil conditions and growth stage may affect responses of these correlations to density via modifying plant size and competition strength. The attenuated canalization and enhanced integration may be helpful for the production of plasticity, especially under intense competition.

The assessment of dispersal potential of the wax cicada Say. (Homoptera: Fulgoroidea: Flatidae) in the agricultural landscape of the Krasnodar Territory vineyards

Цель исследований заключалась в уточнении перечня кормовых растений восковой (белой, цитрусовой) цикадки ( Metcalfa pruinosa Say.) в агроландшафте виноградников и анализе состояния популяции путем определения гендерной структуры в основных зонах виноградарства Краснодарского края. Исследования проводили в 2015-2020 гг. на промышленных насаждениях винограда, в лесополосах и на другой растительности в агроландшафте виноградников согласно общепринятым методикам. Уточнена гостальная пищевая специализация вредителя, к наиболее заселяемым растениям отнесены Gleditsia triacanthos L., Crataegus laevigata Poir., Rosa majalis Herrm., Prunus spinosa L., Rubus fruticosus L., Prunus armeniaca L., Prunus domestica L., Prunus cerasifera Ehrh., Abutilon theophrasti Medik.; установлено отсутствие сортовых предпочтений M. pruinosa при развитии на растениях винограда. Результаты изучения гендерной структуры популяций M. pruinosa показали преобладание самок над самцами в Анапо-Таманской, Черноморской и Южно-предгорной зонах виноградарства Краснодарского края, что позволяет сделать предположение о том, что потенциал расселения восковой цикадки еще не исчерпан, вид продолжает осваивать данную территорию. The aim of the research was to adjust the list of forage plants of the wax (white, citrus) cicada ( Metcalfa pruinosa Say.) in the agricultural landscape of vineyards and to analyze the population conditions by determining the gender structure in the main viticultural zones of the Krasnodar Territory. The research was carried out in 2015-2020 in industrial grape plantings, forest belts and other vegetation in the agricultural landscape of vineyards according to generally accepted methods. The official nutrition specialization of the pest was adjusted, the most populated plants were Gleditsia triacanthos L., Crataegus laevigata Poir., Rosa majalis Herrm., Prunus spinosa L., Rubus fruticosus L., Prunus armeniaca L., Prunus domestica L., Prunus cerasifera Ehrh., Abutilon theophrasti Medik.; the absence of varietal preferences of M. pruinosa when developing on grape plants was established. Results of the study of the gender structure of M. pruinosa populations showed the predominance of females over males in the Anapa-Taman, Black Sea and South-Piedmont zones of viticulture in the Krasnodar Territory, suggesting the potential for dispersal of the wax cicada has not yet been exhausted, the species continues to develop this territory.