Effect of oxygen on the germination and culturability of Bacillus atrophaeus spores

The effect of oxygen on the germination and culturability of aerobic Bacillus atrophaeus spores was investigated in this study. Under oxic or anoxic conditions, various nutritional and non-nutritional germinants were utilized to induce germination. Tb3+-dipicolinic acid fluorescence assay and phase-contrast microscopy were used to track the germination process. The final germination level, germination half time, and germination speed were used to define germination kinetics. Colony-forming unit enumeration was used to assess the culturability of germinated spores germinated with or without oxygen. The results show that in the absence of oxygen, the final germination level was unaffected, germination half time decreased by up to 35.0%, germination speed increased by up to 27.4%, and culturability decreased by up to 95.1%. It is suggested that oxygen affects some germinant receptor-dependent germination pathways, implying that biomolecules engaged in these pathways may be oxygen-sensitive. Furthermore, spores that have completed the germination process in either anoxic or oxic conditions may have different culturability. This research contributed to a better understanding of the fundamental mechanism of germination.

Mobilization of seed storage proteins is crucial to high vigor in common bean seeds

ABSTRACT: Seed germination is a complex process controlled by many factors, in which physical and biochemical mechanisms are involved and the mobilization of reserves is crucial for this process to occur. Although, seed reserve mobilization is usually thought to be a post-germination process, seed reserve proteins mobilization occurs during germination. This study quantified seed proteins of bean genotypes during different hydration times, in order to understand the process of protein mobilization and whether there is relationship of this biochemical component with seed vigor. This study was conducted using seeds with different levels of vigor, genotypes with highest (13, 42, 55 and 81) and lowest (07, 23, 44, 50, IPR-88-Uirapurú and Iapar 81) physiological quality. High vigor genotypes showed greater efficiency in hydrolysis and mobilization of protein component, because they presented low globulins content in cotyledons at radicle protrusion in relation to low vigor genotypes (07, 23 and 50). The protein alpha-amylase inhibitor, observed in all genotypes, is involved with the longer time needed for radicle protrusion, according to the band intensity difference in genotypes 07, 44 and Iapar 81.

High dilutions of Magonia pubescens hidrogel affect germination variables in Sorghum bicolor L. Moench

Introduction: In science homeopathic diseases or physiological disorders are not considered just a result of abiotic and biotic factors, but rather a consequence of loss of organic system homeostasis. Homeopathic science is currently being used efficiently in the control of plagues[1], plant diseases[2], in the increase of medicinal plants’ active principles[3] and in plant metabolism[4,5]. Although actual results, both in the academic and field-level, very little is known about physiological mechanisms action of homeopathic medicine on germination process[6]. This work aims to study the effect of M. pubescens hydrogel, on some physiological variables of sorghum germination (Sorghum bicolor L. Moench). Material and methods: The experiment was conducted at Homeopathy and Plant Physiology of Biology Department at UEM in the period from 04/05/06 to 30/12/06. M. pubescens (tingui) seeds were obtained from the region of Montes Claros - Minas Gerais. The M. pubescens hidrogel was obtained from the external centrals wrappers of 4 dry seeds, after they have been disposed in petri dishes with distilled water for a period of 36 hours of soaking (25oC). The hydrogel mother tincture was prepared according to Manual of Technical Standards for Homeopathic Drugstore[7] 3rd ed (2003), in the proportion of a hidrogel part (5g) to ten parts (50g) of absolute alcohol 70% and stored in a glass amber (capped and protected from light). After 15 days of maceration, the solution was filtered and after 48h at rest, the mother tincture was considered ready for use. The dilution 1cH (Centesimal Hahnemannian) was obtained by adding 0.2 ml of the mother tincture in 19.8 ml of distilled water (1/100) and sucussioned 100 times (33 sucussions s-1) by mechanical arm dynamizer with automatic stop (Model Denise 50 - AUTIC). The subsequent dilutions (2cH to 30cH) were obtained from the same procedure, starting from the dilution 1cH. Bioassay: In petri dish containing 15 seeds of sorghum in a circular distributed were added 10 ml with their dilutions (3, 6, 9, 12, 15, 20 and 30cH) and the control containing distilled water. The petri dishes were placed in a growth chamber (type BOD), temperature of (25 ± 2)°C and photoperiod of 16h. The variables were analyzed by germination period of 73.5h as described below: · Germination (%G): %G = (∑ni.N-1)x100 , where ∑ni, is the total number of germinated seeds in relation to the number of seeds put to germinate, expressed in percentage; · Germination average time (GAT): GAT = ∑ni . ti / ∑ni , where ni is the number of germinated seeds within a certain interval of time ti-1 and ti; expressed in hours. · Germination average speed (GAS), expressed in hours): GAS = ∑ni / ∑ni . ti · Germination speed index (GSI): IVG = G1 / N1 + G2 / N2 + ........ Gn / Nn , where G1, G2....Gn is the number of germinated seeds and N1, N2, ... Nn is the number of hours after sowing. The total number of germinated seeds, at each time (12h) was also analyzed. Seeds were considered germinated when the radicle had 1 to 2 mm of lengths. Experimental design: The experimental design was randomized block with 4 replications, totaling 32 experimental units. It was adopted the double-blind methodology, to avoid possible interference or direction by the researcher. Statistical Analysis: The data were analyzed by ANOVA and the averages compared by Scott-Knott test (p≤0.05). The twinning combined data were analyzed for interaction germination x time (G x T) by F test to 5% of probability. Results and discussion: The homeopathy of Magonia pubescens hydrogel affected on the germination kinetic variables of sorghum seeds, when compared with the control (Fig. 1). This effect was most observed in the initial process of germination (from 13h). Research accomplished by Salgado-Labouriau (1973) [8] showed that the hydrogel formed from the external wrapper Magonia pubescens seeds, does not contain inhibiting, but contains factors that accelerate the germination process. Apparently, these results seem contradictory. However, for the homoeopathic optics, some used medicines in a considered way might have determined effect. Already in high diluted doses this behavior can be reversed, as it happens with some drugs. This behavior in pharmacokinetics is denomined Hormesis. When diluted and given dynamism, the product of hydrogel, instead of stimulating, it can delay the germination for the same phenomenon. Hormesis is not yet explained by science. Homeopathy of the Magonia pubescens gel significantly increased the germination average time (GAT) of sorghum seeds and reduced the germination average speed (GAS) and the germination speed index (GSI) (Fig. 2A, B and C). The values of these variables suggest that homeopathy, somehow slowed the speed of sorghum seeds soaking. Conclusion: The results here presented suggest that high dilutions of Magonia pubescens hidrogel can be used in future experiment such as bioherbicide.

Determination of gushing potential of barley

A new control method for the determination of the malting barley susceptibility to gushing was developed. The method is based on the modified Carlsberg test (MCT) after prior stimulation of barley with substances that promote the germination process. Barleys from the harvest of 2020 and malts produced from them were used to develop and verify the method. The selection of barleys was based on the results of gushing potential detected in the produced malts. To optimise and verify the method, the barley variety Sunshine with a high gushing potential of both barley (139±33 g) and malt (144±13 g), and the barley variety Pionier with zero gushing potential of both barley and malt were used. Malt was produced from the Lodestar barley variety with a high content of the mycotoxin deoxynivalenol. Gushing of the malt was 127±10 g. The gushing potential in barley was determined by the MCT method after prior stimulation of germination. For comparison, the gushing potential was also determined by the MCT method without stimulation of germination. It was proved that stimulation of germination is a key process for correct determination of the susceptibility of barley to gushing. The newly developed method was used for the determination of the gushing potential of five barleys from the harvests of 2020 and 2021. Control gushing determination of five malt samples was performed using the MCT method. An agreement between the measured data was found.

Sorghum in dryland: morphological, physiological, and molecular responses of sorghum under drought stress

Main conclusion Droughts negatively affect sorghum’s productivity and nutritional quality. Across its diversity centers, however, there exist resilient genotypes that function differently under drought stress at various levels, including molecular and physiological. Abstract Sorghum is an economically important and a staple food crop for over half a billion people in developing countries, mostly in arid and semi-arid regions where drought stress is a major limiting factor. Although sorghum is generally considered tolerant, drought stress still significantly hampers its productivity and nutritional quality across its major cultivation areas. Hence, understanding both the effects of the stress and plant response is indispensable for improving drought tolerance of the crop. This review aimed at enhancing our understanding and provide more insights on drought tolerance in sorghum as a contribution to the development of climate resilient sorghum cultivars. We summarized findings on the effects of drought on the growth and development of sorghum including osmotic potential that impedes germination process and embryonic structures, photosynthetic rates, and imbalance in source-sink relations that in turn affect seed filling often manifested in the form of substantial reduction in grain yield and quality. Mechanisms of sorghum response to drought-stress involving morphological, physiological, and molecular alterations are presented. We highlighted the current understanding about the genetic basis of drought tolerance in sorghum, which is important for maximizing utilization of its germplasm for development of improved cultivars. Furthermore, we discussed interactions of drought with other abiotic stresses and biotic factors, which may increase the vulnerability of the crop or enhance its tolerance to drought stress. Based on the research reviewed in this article, it appears possible to develop locally adapted cultivars of sorghum that are drought tolerant and nutrient rich using modern plant breeding techniques.

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 Physical and Chemical Characteristic of 3 Varietas of Germination Brown Rice (Mentik susu, Ciherang, and Pandan wangi)

Brown rice has physical and sensory characteristics that are less favorable despite its high content of nutrition and phytochemical. The germination process is one way to improve and increase the acceptance of brown rice. The objective research was to determine germination time and varieties of brown rice on the physical and chemical characteristics of germinated brown rice. The research was conducted in RAL with 2 factors, germination time (24, 48, and 72 hours) and rice varieties (Mentik susu, Ciherang, and Pandan wangi). The data obtained were processed with analysis of variance to determine the effect of treatment on the parameters tested. If the effect is significant, then to determine the difference between treatments, a Tukey test is performed. Germination time of 24, 48, and 72 hours affected the color, germination, weight, dimensions of lenght, width, and thickness, bulk density, hydration capacity and swelling of germinated brown rice var. Mentik susu, Ciherang, and Pandan wangi. Germination time of 24, 48, 72 hours affected the chemical composition of BCG var. Mentik susu, Ciherang, and Pandan wangi. Based on observations of the physical and chemical characteristics of BCG var. Mentik susu, Ciherang, and Pandan wangi, germination time of 48 hours is recommended to do the germination with germination time of 48 hours compared to germination time of 24 and 72 hours.

Heat activation and inactivation of bacterial spores. Is there an overlap?

Heat activation at a sublethal temperature is widely applied to promote Bacillus species spore germination. This treatment also has potential to be employed in food processing to eliminate undesired bacterial spores by enhancing their germination, and then inactivating the less heat resistant germinated spores at a milder temperature. However, incorrect heat treatment could also generate heat damage in spores, and lead to more heterogeneous spore germination. Here, the heat activation and heat damage profile of Bacillus subtilis spores was determined by testing spore germination and outgrowth at both population and single spore levels. The heat treatments used were 40-80 degrees Celcius, and for 0-300 min. The results were as follows. 1) Heat activation at 40-70 degrees Celcius promoted L-valine and L-asparagine-glucose-fructose-potassium (AGFK) induced germination in a time dependent manner. 2) The optimal heat activation temperatures for AGFK and L-valine germination via the GerB plus GerK or GerA germinant receptors were 65 and 50-65 degrees Celcius, respectively. 3) Heat inactivation of dormant spores appeared at 70 degrees Celcius, and the heat damage of molecules essential for germination and growth began at 70 and 65 degrees Celcius, respectively. 4) Heat treatment at 75 degrees Celcius resulted in both activation of germination and damage to the germination apparatus, and 80 degrees Celcius treatment caused more pronounced heat damage. 5) For the spores that should withstand adverse environmental temperatures in nature, heat activation seems functional for a subsequent optimal germination process, while heat damage affected both germination and outgrowth.

Germination and morphological responses of Triticum aestivum L. to different concentrations of fluoride

A laboratory experiment was conducted on germination papers to study the effect of fluoride (F) at 0 (T1), 50 (T2), 100 (T3), 200 (T4), 250 (T5) and 300 (T6) ppm on germination and morphological parameters in wheat (Triticum aestivum L.) variety, HUW-234 at 2, 4 and 6 days after initiation of germination process. Fluoride toxicity caused reduction in germination per cent, germination index, coefficient of velocity of germination and germination energy (%) while mean germination time increased with fluoride concentration. Root and shoot lengths and dry matters decreased with increased concentrations of fluoride. Ratio of root: shoot weight increased with increased concentration of fluoride. Elongation of seminal roots was adversely affected by increased fluoride level. Increased fluoride level in the germination medium decreased RGR of seedlings progressively. Present study revealed that enhanced fluoride concentration in germination medium caused reduction in germination and germination related parameters.