Abstract
In this study, the allelochemical-induced effects of the leaf water extract of hemp (Cannabis sativa) on seed germination and seedling growth were investigated in durum wheat (Triticum durum) cv. Mongibello and barley (Hordeum vulgare) cv. Alamo. The seeds were imbibed in 25%, 50%, 75%, or 100% solution concentrations, obtained from a 2% hemp leaf extract, and they were germinated at 20 and 10 °C. The 2% extract stock solution (i.e., 100% solution concentration) was obtained by extracting 20 g of leaf powder in 1 L distilled water (2%, w/v). A control of seeds imbibed in distilled water was considered. Germination was scored daily and at the end of the germination test, the final germination percentage (FGP), mean germination time (MGT), germination index (GI), and vigor index (VI) were calculated. The radicles and shoots of the germinated seeds of both species were also measured for their length and weight. The analyses revealed the presence of phenols in the hemp leaf extract, which were the highest in the 100% concentration (13.14 ± 0.20 mg gallic acid equivalent-GAE g−1 extract). At 20 °C, increasing the concentration had either minor (in wheat) or no effects (in barley) on the seed germination. At 10 °C, the germination was reduced by the increasing concentration, suggesting a potential allelopathic effect of the extract. However, at 100% concentration, the seeds germinated significantly better that those at 75% concentration. At 20 °C, increasing concentration progressively depressed both the radicle and shoot elongation in both species. At 10 °C, the radicle elongation was depressed by the extract, irrespective of the concentration, whilst the shoots were as long as those of the control in wheat, and smaller at the 50 and 75% concentrations in barley. We can conclude that the water extract of hemp leaves can have a negative impact on wheat and barley seed germination and seedling growth, particularly at temperatures below optimal. However, the high concentration of phenols in the extract may stimulate seed germination and seedling growth. Thus, in semi-arid areas, such as those of the Mediterranean regions, sowings of wheat and barley after hemp at an optimal (i.e., 20 °C) or nearly optimal temperature are recommended in order to minimize the combined stressing effects of the temperature and allelopathic leaf extract upon plant establishment, which may limit a successful crop establishment.
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Claims 10
Claim · model-written summary
At 10 °C, increasing hemp leaf extract concentration reduced seed germination of wheat and barley.
- Taxon
- wheat and barley
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Hordeum vulgare
Triticum aestivume7 - Treatment
- increasing concentratione1
- Outcome
- germinatione1
- Direction
- reducede1
- Qualifier
- At 10 °Ce1
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
.jpg?width=500)
Verbatim
e1“At 10 °C, the germination was reduced by the increasing concentration, suggesting a potential allelopathic effect of the extract”
e7“a negative impact on wheat and barley seed germination and seedling growth”
Claim · model-written summary
At 20 °C, increasing the extract concentration had a minor effect on seed germination of wheat.
- Taxon
- wheatTriticum aestivume2
- Treatment
- increasing the concentratione2
- Outcome
- seed germinatione2
- Direction
- minore2
- Qualifier
- At 20 °Ce2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“At 20 °C, increasing the concentration had either minor (in wheat) or no effects (in barley) on the seed germination”
Claim · model-written summary
At 20 °C, increasing the extract concentration had no effect on seed germination of barley.
- Taxon
- barleyHordeum vulgaree2
- Treatment
- increasing the concentratione2
- Outcome
- seed germinatione2
- Direction
- no effectse2
- Qualifier
- At 20 °Ce2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e2“At 20 °C, increasing the concentration had either minor (in wheat) or no effects (in barley) on the seed germination”
Claim · model-written summary
At 100% extract concentration, seeds germinated significantly better than at 75%.
- Taxon
- wheat and barleyHordeum vulgareTriticum aestivume7
- Treatment
- 100% concentratione3
- Outcome
- seeds germinatede3
- Direction
- significantly bettere3
- Comparator
- 75% concentratione3
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e3“However, at 100% concentration, the seeds germinated significantly better that those at 75% concentration”
e7“a negative impact on wheat and barley seed germination and seedling growth”
Claim · model-written summary
At 20 °C, increasing extract concentration progressively depressed radicle and shoot elongation in both species.
- Taxon
- wheat and barleyHordeum vulgareTriticum aestivume7
- Treatment
- increasing concentratione4
- Outcome
- radicle and shoot elongatione4
- Direction
- depressede4
- Qualifier
- At 20 °Ce4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e4“At 20 °C, increasing concentration progressively depressed both the radicle and shoot elongation in both species”
e7“a negative impact on wheat and barley seed germination and seedling growth”
Claim · model-written summary
At 10 °C, radicle elongation was depressed by the extract irrespective of its concentration.
- Taxon
- wheat and barleyHordeum vulgareTriticum aestivume7
- Treatment
- the extracte5
- Outcome
- radicle elongatione5
- Direction
- depressede5
- Qualifier
- irrespective of the concentratione5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e5“At 10 °C, the radicle elongation was depressed by the extract, irrespective of the concentration”
e7“a negative impact on wheat and barley seed germination and seedling growth”
Claim · model-written summary
At 10 °C, wheat shoots were as long as those of the control.
- Taxon
- wheatTriticum aestivume6
- Treatment
- the extracte5
- Outcome
- shootse6
- Direction
- as long ase6
- Qualifier
- At 10 °Ce5
- Comparator
- the controle6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e5“At 10 °C, the radicle elongation was depressed by the extract, irrespective of the concentration”
e6“whilst the shoots were as long as those of the control in wheat, and smaller at the 50 and 75% concentrations in barley”
Claim · model-written summary
At 10 °C, barley shoots were smaller at 50 and 75% extract concentrations.
- Taxon
- barleyHordeum vulgaree6
- Treatment
- 50 and 75% concentrationse6
- Outcome
- shootse6
- Direction
- smallere6
- Qualifier
- At 10 °Ce5
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e5“At 10 °C, the radicle elongation was depressed by the extract, irrespective of the concentration”
e6“whilst the shoots were as long as those of the control in wheat, and smaller at the 50 and 75% concentrations in barley”
Claim · model-written summary
The hemp leaf extract had its highest phenol content at 100% concentration.
- Taxon
- hemp
Cannabis sativa subsp. sativae0 - Outcome
- phenolse1
- Direction
- higheste1
- Value
- 13.14 ± 0.20 mg gallic acid equivalent-GAE g−1 extracte1
- Qualifier
- the 100% concentratione1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“the leaf water extract of hemp (Cannabis sativa) on seed germination”
e1“The analyses revealed the presence of phenols in the hemp leaf extract, which were the highest in the 100% concentration (13.14 ± 0.20 mg gallic acid equivalent-GAE g−1 extract)”
Claim · model-written summary
Authors recommend sowing wheat and barley after hemp at an optimal or nearly optimal temperature (20 °C) to limit combined stress.
- Taxon
- wheat and barleyHordeum vulgareTriticum aestivume1
- Outcome
- sowings of wheat and barley after hemp at an optimal (i.e., 20 °C) or nearly optimal temperaturee1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e1“sowings of wheat and barley after hemp at an optimal (i.e., 20 °C) or nearly optimal temperature are recommended”
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