Enhancement of Agro-Industrial Waste Composting Process via the Microbial Inoculation: A Brief Review

Composting is an important technology used to treat and convert organic waste into value-added products. Recently, several studies have been done to investigate the effects of microbial supplementation on the composting of agro-industrial waste. According to these studies, microbial inoculation is considered to be one of the suitable methods for enhancing the biotransformation of organic materials during the composting process. This review provides up-to-date research findings on microbial inoculation strategies and their role and functions in enhancing the composting process and the improvement of compost quality. Based on this review, the addition of microorganisms could enhance the composting process such as accelerating the organic matter degradation, mineralization and microbial enzymes activities, and the quality of the end-products such as high germination index. It is important to notice in this strategy that sludge’s microbial consortium is feasible to enhance the composting process in pilot-scale and industrial-scale productions. Besides, it also reduces the cost of compost production. The findings of this review show the various positive impact of microbial inoculation on agro-industrial waste composting which in turn might be useful as a reference for selecting a suitable inoculum based on the type of waste materials.

The Imbibition, Viability, and Germination of Caper Seeds (Capparisspinosa L.) in the First Year of Storage

The caper is a shrub that adapts to harsh environments when it is established, but it presents serious difficulties in its propagation, both by cuttings and by seeds. Its seeds have low germination percentages, and germination is a very slow process. Significant increases in germination have been obtained with scarification and with the addition of gibberellic acid (GA3) to the substrate, leading to the hypothesis that they have possible physical and physiological dormancy. However, the only way to examine the water-impermeability of the cover is through imbibition analysis. This study analyzes the imbibition, viability, and germination of two seed lots, obtained in different years and evaluated immediately after their collection (FS) and after being stored (7 °C) for one month (DS) and one year (SS). The seed moisture content stabilizes from the fourth day, exceeding in all cases 31% in all three seed states tested (FS, DS and SS). This allows the germination of all viable seeds, only with the addition of GA3 to the germination substrate, without the need for scarification, so that caper seeds exclusively appear to present a physiological latency. Germination decreased in storage, even with just one month. With the GA3 addition, high germination values were obtained (up to 95% in FS).

Biological features of seeds of a wild-growing species of Poterium polygamum

Relevance. Biological features (morphometric indicators, viability and germinating power) of Poterium polygamum seeds found in natural communites of the Stavropol Territory have been studied. The conservation of wild-growing plant species in the natural population and the rational use of their potential are relevant.Methods. Years of study — 2013–2021. The subject of the study is Poterium polygamum seeds. Seeds were collected in 2013. Studies were carried out according to the methods of studying seed material. Freshly harvested seeds and seeds of different shelf life were germinated in petri dishes at a temperature of 18–20 °C.Results. The collected seeds of Poterium polygamum are quite large. The length of the seeds is 4–5 mm, the width is about 2.5 mm. The mass of 1000 pieces of seeds on average was 10.59 grams. Complete absence of viability of freshly harvested Poterium polygamum seeds was revealed. After three months, seed viability was 97%. This is a shallow physiological rest associated with the post-harvest maturation period. During the storage of seeds, their high germination was established — from 70 to 100%. The duration of seed storage is 8 years. The largest number of germinated seeds and their germinating power were noted in the third year of their storage (100%). Seeds germinated on the third or fourth day. The differences between the viability of seeds and their germinating power are not great. In the eighth year of storage of Poterium polygamum seeds, viability and germinating power were slightly reduced. The storage period of seeds, in which they retain the ability to germinate and the germinating power, is long. It has been found that the wild species Poterium polygamum belongs to plants with a high (70 to 100%) viability. This species is regularly resumed in the natural population. The revealed biological features of Poterium polygamum seeds can become the scientific basis during the reconstruction of degraded natural grass stand and in selection work.

Self-pollination of the orchid Cycnoches haagii from Brazilian Cerrado results in albino phenotype seedlings

Cycnoches haagii Barb. Rodr. is an epiphytic orchid very targeted by collectors, but no reference was found in the literature about its reproductive biology. Thus, the purpose of this study was to obtain initial information regarding pollination types and its influence on seed viability of this native orchid of the Brazilian Cerrado, in order to enable future propagation and preservation programs. Pollination among flowers of the same plant (geitonogamy) or different plants (xenogamy) were carried out. Seeds extracted from the capsules were sown in B&G medium, with full and half strength. Seeds from geitonogamic resulted in 25% of albino protocorms and consequently in albino seedlings. This phenomenon did not occur in seedlings derived from xenogamic pollination. Pigment analysis showed that even the albino seedlings presented chlorophylls and carotenoids, however, in significantly minor concentrations, 16% and 37% respectively, in relation to green seedlings. Geitonogamic and xenogamic pollinations resulted in C. haagii viable seeds with high germination percentage (90%) under in vitro conditions. The germination of seeds from xenogamic pollination resulted in chlorophyll or normal seedlings only, and can be recommended at conservation programs. On the other hand, although geitonogamic pollination should be avoided at conservation programs of this orchid species as it leads to albino seedlings, it showed a very interesting system to obtain seedlings with this phenotype, an interesting plant material to future investigation.

Germination biology of the exotic ice cream bean (Inga edulis Mart.) seed from Bedugul, Bali

Inga edulis is an exotic edible Fabaceae species locally known as buah es krim in Bedugul, Bali. The plant species is a favourite fruit for consumption and trading due to the sweet sarcostesta. Wild I. edulis are abundantly grown in Bedugul. The current study aim is to describes I. edulis germination biology. This study will provide data for I. edulis future research both in its domestication and invasion prevention. I. edulis seeds are collected two times from wild plants growing within Bali Botanic Garden. A total of twenty-one I. edulis seeds are germinated in a clear closed plastic container with agar media at Bali Botanic Garden Seed Bank Laboratory. The germination process was observed daily until the seventh day after sowing (DAS) while number of seedlings was calculated in the last observation day. Quantitative and qualitative data analysis was conducted to describe I. edulis seed germination biology. This study result shows that I. edulis seeds produce high germination percentage rapidly. I. edulis seeds exhibited hypogeal germination and phanerocotylar hypogeal with reserve storage seedling functional type. Polyembryony was also present with a single seed can produce up to four seedlings.

The effect of VP3 Biofertilizer and its carrying materials on the germination of six plants

This study investigated the growth after application of VP3 biofertilizer and its essential ingredients (vermiwash and vermicompost) and the effect of their pathogenicity on the germination of soybeans, green beans, long beans, kale, mustard greens, and green spinach. Research design was observed on plant height, root length, fresh weight, and signs of pathogenicity. The VP3 biofertilizer inoculation gave better results than other treatments on the high germination and fresh weight. However, in water spinach plants, the application of VP3 biofertilizer had a significant effect only on the height parameters of the seeds. Provision of VP3 biofertilizer and each of its carriers did not show any signs of pathogenicity such as necrosis, wilting, root rot, or stem rot. This finding indicates that VP3 biofertilizer is potential as a seed treatment and is also known to contain soil-borne disease controlling agent bacteria.

The estimation of Trollius L. species and hybrids by seed germination

The article describes the laboratory germination and seed dormancy duration of five Trollius species andfour hybrids, which has been grew ex situ. The species and forms with high seed germination were detected from the dataobtained: T. ledebourii Rchb. (92 %), T. chinensis Bunge (93,5 %) end T. chinensis × T. ledebourii (82 %). Besides a high germination, the T. ledebourii seeds have the short dormancy period (22 days) and good sprouts. Therefore, the T. ledebourii seeds can be recommended for both autumn and spring sowing. The above mentioned Trollius species and forms arepotential for ornamental cultivar creation by further selection. The seeds of following species and forms T. apertus Perf.ex Igoschina, T. europaeus L., T. sajanensis (Malyschev) Sipliv., T. asiaticus × T. sajanensis, T. ledebourii × T. altaicus and T.× cultorum have low germination and long dormancy period. The examination of stratification treatment parameters andagrotechnical measures is needed for the germination of these seeds to get higher.

Dormancy Breaking Treatments in Northern Wild Rice (Zizania palustris L.) Seed Suggest a Physiological Source of Dormancy

Dormancy is a limiting factor for breeding in northern wild rice (NWR; Zizania palustris L). This study developed a dormancy curve and tested a combination of scarification and hormone treatments, across three timepoints, for their ability to break dormancy in NWR and produce viable seedlings and plants. A dormancy curve was established across 9 months post-harvest, which showed maximum germination (95%) by 17 weeks post-harvest and high germination (≥81 %) through the rest of the testing period. Next, dormancy breaking treatments were tested. At 1 week post-harvest, few seeds germinated (≤ 15 %) across all treatment combinations. However, sulfuric acid increased germination shortly after harvest (5.8 %), compared to water (0.5 %) and NaClO (0 %) but resulted in stunted seedlings, all but one of which died shortly thereafter. At 7 weeks, sulfuric acid treated seeds did not result in significantly higher germination than water and maximum germination was still below 15%. By 11 weeks post-harvest, the water treatments had the highest germination and resulted in the most viable plants, indicating that dormancy had begun to break naturally and exceeded the effect of the other scarification treatments. Hormonal treatments had no significant effect on germination or seed viability and no strong conclusions could be drawn about their effect on seedling or plant health. Due to the inability of early germinated seed to consistently produce viable plants and the increase in germination following sufficient cold storage, it is likely that NWR seed has intermediate or deep physiological dormancy.

Evidence of interpopulation variation in the germination of Eryngium maritimum L. (Apiaceae)

Germination is considered as one of the most crucial steps in a plant’s lifetime. The germination of Eryngium maritimum, a dune species located across all European coasts, has been extensively analysed in Northern populations, where it is considered a locally endangered species. However, less attention has been given to southern populations, where the knowledge about the germination of the species is very limited. The main objective of the present study was to analyse the effect of cold stratification in one Mediterranean and one Atlantic population of the species, as well as to compare the potential variation of seed dormancy among a latitudinal gradient in European populations based on current literature. Seeds collected from Mallorca (Mediterranean, Spain) and Asturias (Atlantic, Spain) were germinated at different temperatures and cold stratification periods ranging from 4 to 20 weeks. These results were merged with the results of previous studies to test the potential effect of latitude and climatic variables in germination. Although the optimal incubation temperature was 10 ºC, the highest final germination percentages (up to 96%) was obtained in both populations combining specific cold stratification periods (5 ºC) and constant incubation temperatures (15–20 ºC). Atlantic seeds needed longer cold stratification times to reach high germination percentages compared with Mediterranean seeds. Apart from the stratification response, significant differences in viability and in germination were observed between the Atlantic and the Mediterranean populations. Considering data from previous studies in the analysis, the results suggest that there is a potential effect of latitude in the ecological germination requirements, by which the higher the latitude, the longer the cold stratification period required to germinate, with a correlation with the mean annual temperature. These results suggests that two factors, modulation of dormancy relating to adaptative or maternal effects and viability, govern the germination of the species.

Effects of protatranes on the germination of wheat and triticale seeds after their long-term storage

The article studies the chemical compounds of a number of protatranes as biostimulants of the germination of wheat and triticale seeds after their long-term storage. The relevance of the study is determined by the need to restore the germination of unique samples of grain crops from the collection of the N.I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR) (Saint Petersburg). The research objects were the seeds of different years of reproduction with various levels of original germination, as well as those with an initially high germination and subjected to accelerated aging. The experiments were conducted in the presence of the following physiologically active non-toxic protatranes 2-Me-C6H4OCH2COO- • HN+(CH2CH2OH)3 (1) and 4-Cl-C6H4SCH2COO-•HN+(CH2CH2OH)3 (2) across a wide range of concentrations (1•10-2 – 1•10-9M). At the first stage, the effect of protatrane 1 on the germination of soft spring wheat was investigated. It was observed that, under the influence of protatrane 1 at concentrations from 10-4 to 10-9 M, the seed germination and the germination energy increased by 8.7-20.0% and 4.7-8.0%, respectively. The use of protatrane 1 at higher concentrations (10-2M) resulted in a decrease in germination. Subsequently, experiments were carried out on 3 samples of soft winter wheat seeds stored for 52 years and having the germination of 19-26%. The 20-hour exposure of seeds to water solutions of protatrane 1 at concentrations of 5 • 10-7-10-9 M increased their germination by 3.7-10.0%. The best stimulating effect was achieved at a concentration of 5 • 10-7 M. At the next stage, the seeds with a high original germination (86-96%) and subjected to accelerated aging were investigated. The treatment of such samples with protatrane 1 at concentrations of 10-6 and 10-4 M turned out to be less effective: the germination and its energy either remained the same or increased insignificantly (by 3.5% and 7.5%, respectively). The treatment of triticale seeds with pro-tatranes 1 and 2 at a concentration of 5 • 10-7 M was carried out in a similar manner. It was shown that the action of protatranes 1 and 2 led to an increase in the germination by 3-7% and a significant increase in the germination energy by 7-45%. By further optimising the production process and selecting the most active protatranes, the described approach can provide for a significant recovery of seed germination.