Root-emitted volatile organic compounds: can they mediate belowground plant-plant interactions?

peer reviewedBackground Aboveground, plants release volatile organic compounds (VOCs) that act as chemical signals between neighbouring plants. It is now well documented that VOCs emitted by the roots in the plant rhizosphere also play important ecological roles in the soil ecosystem, notably in plant defence because they are involved in interactions between plants, phytophagous pests and organisms of the third trophic level. The roles played by root-emitted VOCs in between- and within-plant signalling, however, are still poorly documented in the scientific literature. Scope Given that (1) plants release volatile cues mediating plant-plant interactions aboveground, (2) roots can detect the chemical signals originating from their neighbours, and (3) roots release VOCs involved in biotic interactions belowground, the aim of this paper is to discuss the roles of VOCs in between- and within-plant signalling belowground. We also highlight the technical challenges associated with the analysis of root-emitted VOCs and the design of experiments targeting volatile-mediated root-root interactions. Conclusions We conclude that root-root interactions mediated by volatile cues deserve more research attention and that both the analytical tools and methods developed to study the ecological roles played by VOCs in interplant signalling aboveground can be adapted to focus on the roles played by root-emitted VOCs in between- and within-plant signalling

Mamestra dissimilis Knoch. potential to control weed infestation with mossy sorrel (Rumex confertus Willd.)

Badania polowe i laboratoryjne prowadzono w celu oszacowania możliwości wykorzystania piętnówki zmiennej (Mamestra dissimilis Knoch., Lepidoptera: Noctuidae) do regulacji zachwaszczenia spowodowanego przez Rumex confertus (Willd.). W naturalnym siedlisku szczawiu badano dynamikę jego wzrostu oraz liczbę gąsienic piętnówki zmiennej zasiedlających roślinę w okresie 50 dni. Największą liczbę gąsienic odłowiono pod koniec pierwszej dekady czerwca, w czasie gdy roślina żywicielska miała już w pełni wykształconą rozetę. W warunkach laboratoryjnych badano wzrost masy ciała gąsienic oraz ich żerowanie w temperaturze 20oC. Zależności pomiędzy masą zjedzonych liści szczawiu omszonego a przyrostami masy larw L4 i L5 były statystycznie istotne (r = 0,97 i r = 0,88). Stwierdzono bardzo progresywny charakter żerowania larw L4, opisany równaniem 1. stopnia (r = 0,98). Wyliczono, że każdego dnia w ciągu 20 dni żerowania larwy zjadły o 5,9 mg więcej liści. Natomiast dla gąsienic L5 związek ten miał charakter funkcji 2. stopnia (r = 0,96). Oszacowana masa liści szczawiu omszonego, która uległa skonsumowaniu przez larwy piętnówki zmiennej w warunkach naturalnych, wyniosła 159,3 g, co stanowiło około 11% utraty biomasy żywiciela.Field and laboratory research were conducted to determine the potential of Mamestra dissimilis Knoch., Lepidoptera: Noctuidae to control mossy sorrel (Rumex confertus Willd.). In the natural sorrel habitat a dynamics of the plant growth and the number of Mamestra dissimilis Knoch larvae occurring on that plant over 50 days were researched. The highest number of M. dissimilis larvae was caught at the end of the first decade of June when the host plant rosette was fully developed. In the laboratory, the weight of consumed food by larvae, and larval body weight were measured at 20oC. The relations between the weight of the mossy sorrel leaves consumed and L4 and L5 larvae body weight gains were significant, (r = 0.97 and r = 0.88, respectively). A very progressive feeding of L4 larvae was noted, which was defined by first degree equation (r = 0.98). It was calculated that each day over 20 days of feeding L4 larvae consumed about 5.9 mg more leaves than L5 larvae. For L5 larvae, the relationship was the second degree equation (r = 0.96). An estimated weight of mossy sorrel leaves consumed by M. dissimilis larvae under natural conditions was 159.3 g, which accounted for about 11% loss of the host biomass

Health status of spring barley grown in monocrop and in mixtures with cereals or leguminous plants

In 1997-1999 observations of health status of spring barley grown in two-component mixtures with cereals or pea were performed in two experiments, differing in the agricultural utility of soil. A much better health status of the studied species was found in the mixed crop than in their pure stand. Two-component mixtures were differentiated in the occurrence of leaf diseases caused by Drechslera teres, Drechslera graminea, Puccinia graminis and P. hordei, Rhynchosporium secalis and Erysiphe graminis. The healthiness of lower parts of stem and roots depended on the quality of soil and mixtures factor. A higher infection due to foot root rot complex was noted on barley cultivated on the poorer soil in homogenous stand.W latach 1997-1999 prowadzono obserwacje stanu zdrowotnego jęczmienia jarego uprawianego w dwuskładnikowych mieszankach ze zbożami lub z grochem siewnym. Znacznie lepszy stan zdrowotny u badanego gatunku stwierdzono w uprawach mieszanych niż w siewie czystym. Dwuskładnikowe mieszanki istotnie różniły się między sobą występowaniem objawów powodowanych przez: Drechslera teres, Drechslera graminea, Puccinia graminis i P. hordei, Rhynchosporium secalis i Erysiphe graminis. Zdrowotność podstawy źdźbła i korzeni jęczmienia jarego zależała zarówno od jakości stanowiska, jak i uprawy w mieszankach. Wyższe porażenie przez kompleks patogenów zgorzelowych stwierdzano na słabszej glebie w siewach jednogatunkowych

Responses of spring wheat ‘Monsun’ and spring rye ‘Bojko’ on the late autumn terms of sowing

W latach 2009-2013 przeprowadzono badania na dwóch niezależnych doświadczeniach polowych w Stacji Badawczej Wydziału Rolnictwa i Biotechnologii UTP w Bydgoszczy, zlokalizowanej w Mochlu (gmina Sicienko, województwo kujawsko-pomorskie). Celem było zbadanie reakcji pszenicy jarej 'Monsun' i żyta jarego 'Bojko' na wczesnojesienny i późnojesienny termin siewu w porównaniu z siewem wiosennym. Pszenica wysiewana była na glebie kompleksu pszennego słabego lub wadliwego, żyto na glebie kompleksu żytniego słabego. Obydwa gatunki wysiewano w dwóch terminach jesiennych, tj. jako wczesna przewódka (WP) 30 IX-5 XI, późna przewódka (PP) 10 XI-15 XII i na wiosnę (W) 3 III-5 IV. Pozytywną reakcję w plonie ziarna na jesienne terminy wysiewu stwierdzono u obydwu gatunków. Dla pszenicy 'Monsun' bardziej korzystne pod względem plonowania i jakości ziarna okazały się siewy w późniejszym terminie (listopad-grudzień), a dla żyta 'Bojko' we wcześniejszym terminie siewu (październikowym). Wyższe plonowanie obydwu zbóż po siewie przewódkowym wynikało z lepszego wypełnienia kłosa i dorodności ziarna.To meet the needs for cognitive and practical issues related to the cropping of wheat and rye this study was planned and conducted. The aim of the two independent field trials was to investigate the responses of spring wheat 'Monsun' and spring rye 'Bojko' to the sowing terms in late autumn. The investigation was carried out on the basis of two independent, strict field experiments in 2009-2013, at the Experimental Station of the Faculty of Agriculture and Biotechnology, UTS in Bydgoszcz, located in Mochełek, Kuyavian--Pomeranian region. In the first experiment, the soil of III-IV class according to Polish soil classification, wheat weak or defective complex, investigated the effect of sowing date on yield, yield components and grain quality of spring wheat 'Monsun' includes the following sowing terms: early autumn (early facultative) from 30 September to 5 November; late autumn (late facultative) from 10 November to 15 December, spring from 25 March to 5 April. The same treatments in the second experiment included sowing terms for rye: early facultative 10-15 October, late facultative 5-15 November and spring from 3 March to 1 April. The forecrop for rye was triticale and the soil was V class according to Polish soil classification. Average highest grain yield was obtained after sowing in late autumn terms - 5.83 t∙ha-1, with respect to the average yield of the early facultative crop was higher by 1.03 t. The same wheat sown in the spring obtained an average yield of 5.58 t∙ha-1, which did not differ significantly from late facultative crop. High values of the parameters responsible for the flour and backing obtained from grain, which came from late facultative wheat, e.g. sedimentation rate of 57.5 cm3 and a gluten content of 32.6%. In these respects is superior to wheat sowing spring and early autumn. It was found positive response 'Bojko' spring rye sowing on an earlier facultative term of sowing, i.e. 10-15 of October. The average yield for this date amounted to 3.08 and 0.5 t∙ha-1 was higher than the yield from the date of late autumn and 0.7 t of spring sowing. Higher yields of both cereals after facultative sowings resulted from higher kernels number per ear and grain plumpness

Przydatnosc mieszanek herbicydowych we wspolrzednych uprawach grochu ze zbozami jarymi

W doświadczeniach polowych badano możliwość stosowania herbicydu Chwastox Extra 300 SL (MCPA) oraz jego mieszanek z Baroxem 460 SL (bentazon + MCPA), Basagranem 480 SL (bentazon) lub Bladexem 50 WP (cyjanazyna) do powschodowego zwalczania chwastów we współrzędnych uprawach jęczmienia i owsa z grochem pastewnym. Stwierdzono, że Chwastox (3,0 dm³·ha⁻¹), Chwastox + Barox (2,5 + 1,0 dm³·ha⁻¹), Chwastox + Basagran (2,5 + 1,0 dm³·ha⁻¹), Chwastox + Bladex (2,5 dm³·ha⁻¹ + 0,5 kg·ha⁻¹) były dobrze tolerowane przez rośliny uprawne i skutecznie ograniczały zachwaszczenie. Przydatność wszystkich tych wariantów herbicydowych okazała się równorzędna i korzystna dla wielkości plonu testowanych upraw. Herbicydy Chwastox Extra 300 SL w dawkach do 3 dm³·ha⁻¹, Barox 460 SL w dawkach do 4 dm³·ha⁻¹ oraz Bladex 50 WP w dawce 0,5 kg·ha⁻¹ nie powodowały trwałych uszkodzeń roślin jęczmienia jarego, owsa i grochu.Usefulness of MCPA active ingridience (commercial product named Chwastox Extra 300 SL) and herbicide mixtures consisting of MCPA and different kind of active substances such as: bentazon + MCPA (Barox 460 SL), bentazon (Basagran 480 SL) or cyanazin (Bladex 50 WP) was investigated in the field as postemergency treatment against weeds infestation at cereal-pea mixed stands. Each of the applied herbicide and their doses: Chwastox (3 dm³·ha⁻¹), Chwastox + Barox (2.5 + 1 dm³·ha⁻¹), Chwastox + Basagran (2.5 + 1.0 dm³·ha⁻¹) and Chwastox + Bladex (2.5 dm³·ha⁻¹ + 0.5 kg·ha⁻¹) revealed a high level of weed control and the protected plants were entirely resistant to these treatments. Chwastox and its 2-components mixtures equatly affected the crop yielding. Maximal doses were also tested for spring barley, oats and field pea. Chwastox Extra at 3 dm³·ha⁻¹, Barox at 4 dm³·ha⁻¹ and Bladex at 0.5 kg·ha⁻¹ damaged neither cereals nor field pea plants

Volatile induction of infected and neighbouring uninfected plants potentially influence attraction/repellence of a cereal herbivore

Pathogen infection can induce plant volatile organic compounds (VOCs). We infected ‘McNeal’ wheat and ‘Harrington’ barley with a Fusarium spp. blend (F. graminearum, F. avenaceum and F. culmorum). Both cereals had the greatest VOC induction 14 days after pathogen innoculation, only slightly lower induction occurred at 7 days, but displayed no induction at 1 days. The induced VOC bouquet for both cereals included six green leaf volatiles (GLVs; e.g. (Z)-3-hexenol and (Z)-3-hexenyl acetate), four terpenes (linalool, linalool oxide, (Z)-β-ocimene and (E)-β-caryophyllene) and benzyl acetate. Neighboring, uninfected individuals of both cereals had significant VOC induction when exposed to an infected, conspecific plant. The temporal pattern and VOC blend were qualitatively similar to infected plants but with quantitative reductions for all induced VOCs. The degree of neighbouring, uninfected plant induction was negatively related to distance from an infected plant. Plant VOC induction in response to pathogen infection potentially influences herbivore attraction or repellency. Y-tube tests showed that herbivorous female and male Oulema cyanella Voet. (Chrysomelidae: Coleoptera) were significantly attracted to (Z)-3-hexenal and (Z)-3-hexenyl acetate at 300 and 1500 ng/h but were repelled by both GLVs as well as (Z)-β-ocimene and linalool at 7500 ng/h. These O. cyanella behavioral responses were significantly at higher concentrations than those emitted by single plants with pathogen-induced VOCs, so adults might only be able to respond to a dense group of infected plants. Also, O. cyanella dose responses differ from the previously tested congeneric O. melanopus (cereal leaf beetle), which was attracted to three VOCs induced by Fusarium infection of maize, barley and wheat. Future behavioral tests may indicate whether different herbivore dose responses measured with each VOC singly can help to predict attraction or repellency to injured and uninjured VOC bouquets from different host plant species

Fitosanitarna funkcja owsa i mieszanek z jego udzialem w ogniwie zmianowania

Badania dotyczyły fitosanitarnej roli owsa w ogniwie zmianowania zbożowego, składającego się z jęczmienia jarego jako przedprzedplonu, owsa w siewie czystym lub w mieszankach z jego udziałem jako przedplonu i pszenicy ozimej jako rośliny następczej. Określono stopień porażenia korzeni i podstawy pędów zbóż uprawianych w przedplonie pszenicy ozimej oraz porażenie samej pszenicy ozimej. Wartość przedplonową owsa i mieszanek z jego udziałem dla pszenicy rozpatrywano także w kontekście wydajności tego gatunku.Investigations concerned the phytosanitary function of oats in cereal crop rotation consisted of: spring barley as fore-forecrop, oats and their mixtures as forecrop for winter wheat, cultivated on good rye soil complex. Infection level of roots and stem base in cereal forecrops of wheat were estimated and recalculated into infection indices. Health status of wheat lower stems and roots were also recognised. Oats in pure sowing and mixed with other crops were evaluated as forecrops to winter wheat in context of wheat yielding

Wpływ dawki azotu i międzyplonów ścierniskowych na zawartość makroelementów w ziarnie pszenicy jarej

The aim of this study was to determine the effect of different rates of nitrogen ferti- lizer and stubble catch crops on the content of nitrogen, phosphorus, potassium and ma- gnesium in the grain of spring wheat. Field experiment was carried out in 2005-2008 at Moche3ek near Bydgoszcz (53° 13' N, 17° 51' E) on the Alfisols soil classified as a very good rye complex and IIIb quality class. Nitrogen fertilization was applied at the rates of (kg N ha ?1 year ?1 ): 0; 40 (before sowing), 80 (40 kg before sowing and 40 kg in BBCH 31-32 stage), 120 (60 kg before sowing and 60 kg in the BBCH 31 ? 32 stage) and 160 (60 kg before sowing and 60 kg in BBCH 31-32 stage and 40 kg in BBCH 45-47 stage). Stubble catch crops (field pea and oilseed radish) were sown in the period from 3 to 11 of August in 2005 to 2007. After 70-77 days of plant growing, the whole biomass was plowed in as green manure. Spring wheat cv. Tybalt was sown following the catch crop,between March 30 to April 11 in 2006 to 2008. Nitrogen fertilization affected the concentrations of N, P and Mg in grain of spring wheat. Every 40 kg increment of nitrogen fertilization per ha resulted in a significant increase in the N content in wheat grain. The concentration of Mg in spring wheat grain was significantly higher when nitrogen fertilization was dosed at 120 or 160 kg per ha than at lower doses. The phosphorus content in grain of wheat grown after field pea catch crop was not related to nitrogen fertilization rates, while after the radish and in the control (without catch crop), it was significantly higher at 120 and 160 kg N per ha than at 40 kg N per ha. No effect of nitrogen fertilization on the K concentration in grain of spring wheat was found. Mean values from the three years of the N and Mg content in the grain of spring wheat were significantly influenced by the stubble catch crops. The effect of this factor on the content of macroelements in spring wheat grain was detected only in 2008, which had very low rainfalls during the growth of plants. Under these conditions, the stubble catch crops caused an increase in the content of N and a decrease of P and Mg in grain