Drought Stress Influences the Growth and Physiological Characteristics of Solanum rostratum Dunal Seedlings From Different Geographical Populations in China

Extensive studies have shown that the success of invasive plants in large environmental gradients can be partly attributed to related factors, including phenotypic plasticity and rapid evolution. To enhance their ability to compete and invade, invasive plants often show higher morphological and physiological plasticity to adapt to different habitat conditions. In the past two decades, invasive species have expanded to some new habitats in North and Northwest China, including arid oasis agricultural zones, which are disturbed by human activities, and the ecosystem itself is very fragile. To evaluate the ecological adaptability of invasive plants widely distributed in North and Northwest China, we studied the physiological response and tolerance mechanism of different geographical populations of Solanum rostratum Dunal to different drought-stress gradients in extremely arid regions (Xinjiang population) and semi-arid regions (Inner Mongolia population). The results showed that with the aggravation of drought stress, S. rostratum from different geographical populations adopted different physiological mechanisms to drought stress. Xinjiang population was mostly affected by root/shoot ratio and chlorophyll fluorescence characteristics, showing higher plasticity in the net and total photosynthetic rates, while the Inner Mongolia population mainly relied on the accumulation of osmotic adjustment substances, higher leaf dry matter content, and increased malondialdehyde to cope with drought stress. Based on these results, we concluded that the physiological responses of S. rostratum invading different habitats in northern China to drought stress were significantly different. The drought resistance of the Xinjiang population was higher than that of the Inner Mongolia population. In general, S. rostratum can be widely adapted to both harsh and mild habitats through phenotypic plasticity, threatening agricultural production and ecological environment security in northern China.

Аналіз фітосанітарного стану Херсонської області за поширенням карантинних бур’янів

Мета дослідження – аналіз фітосанітарного стануХерсонської області за поширенням карантинних бур’я-нів, зазначених у списку А–2 «Перелік регульованихшкідливих організмів» і визначення тенденцій зміни зас-мічених площ за окремими видами. Методи. Аналіз про-ведено у період з 01.01.2016 до 01.01.2021 рр. на основіданих Державної служби України з питань безпечностіхарчових продуктів та захисту споживачів за такимивидами обмежено поширених карантинних бур’янів:гірчак повзучий Acroptilon repens L., амброзія полино-листа Ambrosia artemisiifolia L., ценхрус довгоголковийCеnchrus longispinus Fernald, повитиця польова Cuscutacampestris Junk. та паслін колючий Solanum rostratum Dunal. Під час дослідження використовували загаль-нонаукові методи, застосовували варіаційний методматематичної статистики. Результати. Забур’яненаамброзією полинолистою площа станом на перше січня2016–2021 рр. зменшилася від 277011,3 до 275350,6 га.Площа, засмічена гірчаком повзучим, скоротилася від203162,4 до 199808,6 га і залишалася стабільною про-тягом останніх трьох років. Станом на 01.01.2016 р. цен-хрус довгоголковий зареєстровано на площі 21606,5 га,з 01.01.2017 р. площа його поширення зменшилася до20052,2 га та була незмінною останні п’ять років. Площа,забур’янена повитицею польовою, скоротилась у дослі-джуваний період від 6052,7 до 5242,0 га. Паслін колючийна території країни було виявлено тільки в Херсонськійобласті на площі 134,0 га. Аналіз структури площ, засмі-чених обмежено поширеними видами бур’янів, свідчитьпро те, що основну їхню частину в Херсонській областізареєстровано в господарствах усіх форм власності.Паслін колючий був поширений тільки в господарствах.Висновки. У період із 01.01.2016 до 01.01.2021 рр.у Херсонській області спостерігалася тенденція змен-шення площ, засмічених гірчаком повзучим, амброзієюполинолистою, ценхрусом довгоголковим та повити-цею польовою. Ступінь варіювання площ поширеннязазначених видів бур’янів за роками був незначним, щопідтверджується результатами статистичного аналізу.Незмінною в Херсонській області залишалася площапасльону колючого.

Effect of Herbicides on the Management of the Invasive Weed Solanum rostratum Dunal (Solanaceae)

Solanum rostratum Dunal is an invasive weed species that invaded Israel in the 1950s. The weed appears in several germination flashes, from early spring until late summer. Recently, an increase in its distribution range was observed, alongside the identification of new populations in the northern part of Israel. This study aimed to investigate the efficacy of herbicide application for the control of S. rostratum using two field populations originated from the Golan Heights and the Jezreel Valley. While minor differences in herbicide efficacy were recorded between populations, plant growth stage had a significant effect on herbicide response. Carfentrazone-ethyl was found to be highly effective in controlling plants at both early and late growth stages. Metribuzin, oxadiazon, oxyfluorfen and tembutrione showed reduced efficacy when applied at later growth stage (8–9 cm height), as compared to the application at an early growth stage (4–5 cm height). Tank mixes of oxadiazon and oxyfluorfen with different concentrations of surfactant improved later growth stage plant control. Taken together, our study highlights several herbicides that can improve weed control and may be used as chemical solutions alongside diversified crop rotation options. Thus, they may aid in preventing the spread and further buildup of S. rostratum field populations.

Biomechanical properties of a buzz-pollinated flower

Approximately half of all bee species use vibrations to remove pollen from plants with diverse floral morphologies. In many buzz-pollinated flowers, these mechanical vibrations generated by bees are transmitted through floral tissues, principally pollen-containing anthers, causing pollen to be ejected from small openings (pores or slits) at the tip of the stamen. Despite the importance of substrate-borne vibrations for both bees and plants, few studies to date have characterized the transmission properties of floral vibrations. In this study, we use contactless laser vibrometry to evaluate the transmission of vibrations in the corolla and anthers of buzz-pollinated flowers of Solanum rostratum , and measure vibrations in three spatial axes. We found that floral vibrations conserve their dominant frequency (300 Hz) as they are transmitted throughout the flower. We also found that vibration amplitude at anthers and petals can be up to greater than 400% higher than input amplitude applied at the receptacle at the base of the flower, and that anthers vibrate with a higher amplitude velocity than petals. Together, these results suggest that vibrations travel differently through floral structures and across different spatial axes. As pollen release is a function of vibration amplitude, we conjecture that bees might benefit from applying vibrations in the axes associated with higher vibration amplification.

OCCURRENCE OF SOLANUM ROSTRATUM DUNAL IN NORTHERN BALOCHISTAN – FIRST RECORD FOR PAKISTAN

Solanum rostratum Dunal is native to the United States of America and northern and central Mexico. Solanum rostratum has been observed in various localities in Zhob district of northern part of Balochistan Province of Pakistan. These observations represent first record of this species from Balochistan or Pakistan. Its description and illustrations are provided for easy identification.