This study evaluated the chronic toxicity (30 days) of different sizes of polyethylene terephthalate (PET) microplastics (60–3000 μm) provided alone or in combination with acid rain, on garden cress ...(Lepidium sativum). Both biometrical and physiological traits have been evaluated: i) percentage inhibition of seed germination, plant height, leaf number and fresh biomass production; ii) oxidative stress responses (hydrogen peroxide; ascorbic acid and glutathione production); iii) impairment in photosynthetic machinery in term of pigments production; iv) aminolevulinic acid and proline production. Results highlighted that different sizes of PET, alone or in combination with acid rain, are able to negatively affect both biometrical and physiological plant traits. In particular, the lower size of microplastics is able to negatively affect growth and development, as well as to trigger the oxidative burst. Regarding the pigments production, PET coupled with acid rain, induced a higher production of Chl-b, and an inhibition of aminolevulinic acid.
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•L. sativum was exposed to PET alone or coupled with acid rain.•Lower size of PET most negatively affects growth and development of garden cress.•PET alone or coupled with acid rain triggers oxidative burst.•PET with acid rain negatively affect: AsA, Chl a and AlA productions.•Higher AlA values correspond to higher proline values.
PET microplastics (60–3000 μm), alone or in combination with acid rain, are able to negatively affect both biometry and physiology of L. sativum, depending to different particle size.
Introduction:
Phosphorus plays a range of functions in the proper growth and development of plants. Numerous microbial species, including bacteria, fungi, actinomycetes, and even algae have been ...found to play a crucial role in the solubilization of phosphate. This study was therefore aimed at exploring the growth-promoting potential of phosphate solubilizing
Enterobacter
species on maize and cowpea seedlings.
Methods:
Five strains that showed remarkable phosphate solubilization potential were used for the study. The bacterial isolates consist of three strains of
Enterobacter cloaca
and two strains of
Enterobacter hormaechei
. Growth promotion studies were carried out under laboratory conditions (in blotters) and green house (soil environment). In the blotter study, percent germination, germination index, germination time, germination rate, and vigor index were estimated, while shoot and root lengths, number of leaves, and wet weight were estimated in the greenhouse study.
Results:
In both seedlings, percent germination, germination index, and vigor index showed significantly higher values in seeds primed with the isolates than in the water-treated seeds (p≤ 0.05). Throughout the period of planting, the shoot and root lengths of the isolate-treated seedlings showed significantly higher values than the untreated control setups. This observation was irrespective of the maize and cowpea seedlings. In both seedlings, shoot and root lengths were directly proportional to days of growth. The bacterial strains showed significantly higher growth promoting potential on the seedlings.
Conclusion:
Therefore, the availability of these phosphate solubilizing microorganisms in the soil could enhance the growth of the seeds.
During the study, the seeds of seven sweet basil cultivars were treated with 100 ppm solutions of gibberellic acid or ascorbic acid prior to a 14-day germination experiment. Values of the first day ...of germination, germination energy, germinability, mean time and rate of germination, and uncertainty and synchrony of germination were calculated. The results show that both of the substances altered the measured parameters, priming with gibberellic acid proving to be a more effective way to enhance the germination of basil seeds. Also, they revealed major differences among the germination parameters of the examined cultivars.
Premise
Declines in reproductive capabilities with increasing age are common across the tree of life. However, in plants, mating system traits have rarely been tested for signs of senescence. Since ...reproduction is often resource limited, we might expect outcrossing and selfing taxa to allocate these resources differently, especially as a plant ages. Compared with selfers, outcrossers are expected to produce showy, rewarding flowers that attract pollinators and high‐quality pollen that can successfully compete for ovules. Yet, this resource‐intensive strategy of outcrossers may result in declines in floral allocation and pollen performance metrics, relative to selfers.
Methods
To explore age‐related changes in reproduction, we measured flower size and pollen germinability over the flowering period for multiple populations of an annual sister species pair, Collinsia linearis (outcrosser) and C. rattanii (selfer), in a growth chamber experiment.
Results
We found that flower size decreased significantly with age in both species. The outcrosser expressed a significant and dramatic (88%) decline in pollen germinability with age, while the selfer's pollen germinability decline was non‐significant and low (17%).
Conclusions
Our results support the idea that the higher total cost of reproduction in outcrossers can deplete available resources more rapidly than in selfers, manifesting as a decline in male performance with plant age.
The growing demand for native seeds in ecological restoration and rehabilitation, whether for mining, forest, or ecosystem restoration, has resulted in a major global industry in the sourcing, ...supply, and sale of native seeds. However, there are no international guidance documents for ensuring that native seeds have the same standards of quality assurance that are regular practice in the crop and horticultural industries. Using the International Principles and Standards for the Practice of Ecological Restoration as a foundation document, we provide for the first time a synthesis of general practices in the native seed supply chain to derive the Principles and Standards for Native Seeds in Ecological Restoration (“Standards”). These practices and the underpinning science provide the basis for developing quality measures and guidance statements that are adaptable at the local, biome, or national scale. Importantly, these Standards define what is considered native seed in ecological restoration and highlight the differences between native seeds versus seeds of improved genetics. Seed testing approaches are provided within a logical framework that outline the many different dormancy states in native seed that can confound restoration outcomes. A “pro‐forma” template for a production label is included as a practical tool that can be customized for local needs and to standardize reporting to end‐users on the level of seed quality and germinability to be expected in a native seed batch. These Standards are not intended to be mandatory; however, the guidance statements provide the foundation upon which regulatory approaches can be developed by constituencies and jurisdictions.
The interspecific hybridization was performed between five tulip cultivars, including ‘Judith Leyster,’ ‘World’s Favorite,’ ‘Heart of Poland,’ ‘Crispa Fabio’ and ‘Jumbo Pink,’ and five wild species, ...including
Tulipa thianschanica
Regel,
T. sinkiangensis
Z. M. Mao,
T. altaica
Pall. ex Spreng,
T. buhseana
Boiss. and
T. schrenkii
Regel., to explore the cross-compatibility between tulip cultivars and wild species. In this experiment, pollen size and germinability, pollen storage life, stigma receptivity, fruit-setting, hybrid seed germination and bulblet formation were observed. The chromosome count and karyotype of hybrids were also examined. The results showed that
T. altaica
and five cultivars had closer genetic relationship than the other four wild species. Among the five wild
Tulipa
species
T. altaica
has the largest pollen and the highest germination rate (65.23%) compared with any other four species. The pollen viability of all five pollen parents decreased slowly across all stages at − 20 °C and decreased rapidly at 25 °C and 4 °C. A total of 1066 hybrids were obtained from interspecific hybridization combinations, including ‘Heart of Poland’ ×
T. thianschanica
, ‘Heart of Poland’ ×
T. altaica
, ‘Crispa Fabio’ ×
T. altaica
, ‘Jumbo Pink’ ×
T. altaica
, ‘Crispa Fabio’ ×
T. schrenkii
and ‘Jumbo Pink’ ×
T. schrenkii
. According to the chromosome count, approximately 20% and 12% aneuploidy hybrids were produced from ‘Heart of Poland’ (2
n
= 3
x
= 36) ×
T. thianschanica
(2
n
= 2
x
= 24) and ‘Heart of Poland’ (2
n
= 3
x
= 36) ×
T. altaica
(2
n
= 2
x
= 24), respectively, and the any other hybrids were diploid (2
n
= 24) in these two crosses. All the hybrids from crosses of diploid parents were diploid (2
n
= 24). Meanwhile, the karyotype characteristics of six parents and their six progenies were also elaborated, which had similar 3A and 3B karyotypes. The results of this study may facilitate tulip interspecific hybridization in the future.
Acacia dealbata is an invasive southeastern Australian tree that produces a persistent soil seed bank. In order to characterize the seed bank in plots invaded by A. dealbata and to understand its ...implications for management and re-invasion risk, density, germinability, and viability of the seed bank were evaluated in five sites in central Portugal. Soil samples were collected in A. dealbata invaded plots and adjacent areas and screened for seeds, which were then quantified and germinated at 25 °C. A subset of seeds was first exposed to 60 °C to assess the effect of high soil temperature on dormancy breaking. Variables influencing differences between sites were explored with generalized linear mixed models with a Poisson distribution. Inside A. dealbata invaded plots the seed bank averaged 4608 seeds/m², reaching up to 62,747 seeds/m²; in adjacent areas, up to 14 m from the plots, only 9 seeds/m² were found. Seed bank densities were mostly influenced by stoniness, number of fires in the last 10 years, and density of trees and roots. Almost 90% of seeds were viable, but only 8.6% germinated without treatment. Nearly 70% of seeds exposed to 60 °C germinated without any physical stimulation, suggesting that high soil temperatures can effectively break seed dormancy. The high density and viability of A. dealbata's seed bank and its ability to disperse seeds far from the parent plants contribute to the species' invasive success. These features combined with heat events that can overcome seed dormancy need to be considered in the management of this species.
Rice growth is sensitive to low temperature. Chilling injury is one of the main natural disasters in rice cultivation, and is damaging to rice growth at all developmental stages. Low-temperature ...germinability (LTG) is an important trait for seedling establishment, especially in rice direct-sowing practice. However, the genetic mechanism of LTG remains elusive. Here, we report the mapping of QTLs controlling LTG in rice using 586 single segment substitution lines (SSSL) derived from 4 AA-genome wild rice species. 21 SSSLs with the highest germination rate at low temperature in both of the two tested seasons were selected, from them 10 QTLs controlling LTG were identified by substitution mapping to locate on 6 chromosomes: chromosome 1, 3, 5, 7, 8 and 11, with an interval length of 3.45 to 20.15 cM. Five QTLs were detected from Niv-SSSls:
qLTGn3-1
,
qLTGn5-1
,
qLTGn5-3
,
qLTGn7-1
and
qLTGn7-2
, their additive effects ranged from 3.72% to 19.74% in late season 2018.
qLTGb1-1
and
qLTGb8-2
were detected in the SSSLs with
O. barthii
as the donor and they accounted for at least 9.51% of the total phenotypic variation. Two QTLs,
qLTGg5-2
and
qLTGg8-1
, were derived from
O. glumaepatula,
and their average additive effects were 4.28% and 20.39% in late seasons 2018, respectively.
qLTGm11-1
on chromosome 11 was the only QTL identified from
O. meridionalis
. All QTLs derived from wild rice species improved low-temperature germination significantly. The SSSL library with wild rice species as donor is therefore a valuable resource for rice germplasm innovation and the breeding of chilling-resistant varieties.
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