Total Starch Content Research Articles

Changes in physicochemical properties and microbial community succession during leaf stacking fermentation

Leaf stacking fermentation involves enzymatic actions of many microorganisms and is an efficient and environmentally benign process for degrading macromolecular organic compounds. We investigated the dynamics of metabolite profiles, bacterial and fungal communities and their interactions during fermentation using cigar leaves from three geographic regions. The results showed that the contents of total sugar, reducing sugar, starch, cellulose, lignin, pectin, polyphenol and protein in cigar tobacco leaves was significantly decreased during fermentation. Notably, the furfural, neophytadiene, pyridine, benzyl alcohol, geranylacetone, 3-hydroxy-2-butanone, N-hexanal, 3-Methyl-1-butanol and 2,3-pentanedione were important features volatile aroma compounds during fermentation. The α-diversity of fungi and bacteria initially increased and then decreased during fermentation. An analysis of variance showed that microbial diversity was influenced by fermentation stages and growing locations, in which the all stages had greater impacts on α- and β-diversity than all regions. Microbiome profiling had identified several core bacteria including Sphingomonas, Bacillus, Staphylococcus, Pseudomonas, Ralstonia, Massilia and Fibrobacter. Fungal biomarkers included Aspergillus, Penicillium, Fusarium, Cladosporium and Trichomonascus. Interestingly, the molecular ecological networks showed that the core taxa had significant correlations with metabolic enzymes and physicochemical properties; bacteria and fungi jointly participated in the carbohydrate and nitrogen compound degrading and volatile aroma compound chemosynthesis processes during fermentation. These studies provide insights into the coupling of material conversion and microbial community succession during leaf fermentation.Graphical abstract

Assessment of G × E interaction and stability parameters for quality, root yield and its associating traits in ashwagandha [Withania somnifera (L.) Dunal] germplasm lines

Withania somnifera (L.) Dunal holds significant pharmaceutical and nutritional benefits. The stability and superior root yield of ashwangandha genotype is a crucial parameter for long-term development and raw material supply for pharma-industries. The impact of genotype × environment (G × E) interaction on economic traits (root yield) stability on ninety-six genotypes in four different environments was evaluated in this study. Using two models of stability analysis namely Eberhart - Russell and Additive Main Effects and Multiplicative Interaction (AMMI) analysis models, current study was focused on adaptability and phenotypic stability of ashwangandha genotypes. Field trail was conducted in a randomized complete block design with three replications. Phenotypic data were collected on eleven important traits including four commercially important traits viz total soluble sugars (TSS), starch content, withanolides content and crude fiber in the main and late-season in 2020 and 2021. Analysis of variance exhibited consistency between both models. These results depicated G × E interaction, revealing subtle variations in response to environmental conditions. Eberhart and Russell model provided valuable trait performance insights, while AMMI offered genotype and environment insights. Interestingly, Eberhart and Russell model identified Env 3 as superior while Env 4 as a challenging environment. Genotypes viz. AGP-84, AGP-16, AGP-79, AGP-95, AGP-57 and AGP-14 exhibited stability and consistent performance for root yield across environments. AMMI analysis captured 52.7 % variance in the first principal component and 26.3 % in the second. Genotypes namely AGP 18, AGP 22, and AGP 57 were found best and stabile with high mean dry root yield in both models. Env 1 stood out as the most distinct, and Env 2 was representative for selecting the best genotypes.

East African highland cooking banana: towards an efficient selection of hybrids with user-preferred food quality traits.

Determinants of culinary qualities of East African highland cooking bananas (EAHCB) are not well known. This constrains the inclusion of user-preferred traits in breeding. The present study aimed to quantify key indicators of user-preferred characteristics to enable selection of acceptable hybrids. Qualitative characteristics that drive preference were big bunches (15-34 kg), long straight/slightly curved fingers (12-23 cm), yellowness and soft texture. Descriptive sensory analysis of the intensity of colour and texture the 23 genotypes revealed that landraces Kibuzi, Mbwazirume, Nakitembe and Mpologoma had higher intensity of yellowness and lower intensity of hardness (softer) and a low score (≤ 1.0) of astringency taste. A preference test showed that they had higher acceptability scores. Biochemical, instrumental and sensory data revealed correlations between sensory firmness and instrumental hardness (r = 0.5), sensory firmness and amylopectin (r = -0.54), suggesting that qualitative descriptions can be predicted by instrumental and biochemical indicators. Significant (P < 0.05) variations in amylose and total starch content were observed in different varieties. Moderate correlations between instrumental hardness and firmness in mouth (r = 0.55), cohesiveness and firmness in the mouth (r = 0.57), and adhesiveness and firmness in the mouth (r = 0.64) were observed. Surprisingly, carotenoids content was not correlated with yellowness in cooked matooke. However, positive correlations were observed between chroma (b*) parameters of raw matooke and sensorial assessed color on cooked samples. Qualitative characteristis; the bunch, pulp colour and texture; that drive users-preference in the EAHCB were quantified, paving way for breeders to use them to select genotypes with these attributes early in the breeding process. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Comparative Effects of Heat Stress at Booting and Grain-Filling Stage on Yield and Grain Quality of High-Quality Hybrid Rice.

Rice plants are highly sensitive to high-temperature stress, posing challenges to grain yield and quality. However, the impact of high temperatures on the quality of high-quality hybrid rice during the booting stage, as well as the differing effects of the booting and grain-filling stages on grain quality, are currently not well-known. Therefore, four high-quality hybrid rice were subjected to control (CK) and high-temperature stress during the booting (HT1) and grain-filling stages (HT2). Compared to the control, HT1 significantly reduced the spikelets panicle-1 (16.1%), seed setting rate (67.5%), and grain weight (7.4%), while HT2 significantly reduced the seed setting rate (6.0%) and grain weight (7.4%). In terms of quality, both HT1 and HT2 significantly increased chalkiness, chalky grain rate, gelatinization temperature, peak viscosity (PV), trough viscosity (TV), final viscosity (FV), and protein content in most varieties, and significantly decreased grain length, grain width, total starch content, and amylose content. However, a comparison between HT1 and HT2 revealed that the increase in chalkiness, chalky grain rate, PV, TV, and FV was greater under HT2. HT1 resulted in a greater decrease in grain length, grain width, total starch content, and amylose content, as well as an increase in protein content. Additionally, HT1 led to a significant decrease in amylopectin content, which was not observed under HT2. Therefore, future efforts in breeding and cultivating high-quality hybrid rice should carefully account for the effects of high temperatures at different stages on both yield and quality.

Nutrient profiling of Wild Aonla (Emblica officinalis Gaertn.) populations in Northeast India: Assessing the potential of this fruit tree for ecological and human health restoration

Assessing the potential of native species like Emblica officinalis (Aonla) is vital for various reasons. It supports biodiversity conservation, sustainable agriculture, ecological equilibrium, human well-being, and climate resilience. This study, conducted across 30 diverse locations in Arunachal Pradesh, Northeast India, unveiled substantial morphological and nutrient variations among Aonla genotypes. Notable findings include G24's high total soluble solids content, G1's maximum acidity, and G13's elevated total carbohydrate content. G29 stood out with increased pectin, vitamin C, and phosphorus, while G19 exhibited higher total chlorophyll, carotenoids, and potassium. Additionally, genotypes displayed differences in crude protein, total starch, crude fibre, and total phenol content. Four promising genotypes (G29, G19, G24, and G1) hold the potential for genetic crop enhancement, offering benefits in local nutrition, health, soil quality, and water retention, not only in Northeast India but also beyond. This research underscores the significance of understanding and utilizing native resources to foster both ecosystems and human communities.

How storage circumstance alters the quality of seeds of Lallemantia iberica and Lallemantia royleana produced under maternal drought stress

Seed production underpins the agricultural industry and is impacted by the maternal environment during maturation. In addition, inappropriate post-harvest storage conditions can affect seed quality, by accelerating viability loss and reducing seed longevity. The objective of this research was to investigate the impact of storage conditions on the germination and physiological and biochemical processes of seeds of Lallemantia iberica and L. royleana under drought stress. Seeds were matured under maternal plant irrigation regimes of 30% (I30) and 60% (I60) of soil available water depletion and subjected to different storage conditions: control, natural aging (NA), controlled deterioration (CD), elevated partial pressure of oxygen (EPPO), and elevated partial pressure of nitrogen (EPPN). Seeds of both species matured under water deficit I60 had enhanced germination index, unsaturated and saturated fatty acid contents, total soluble sugar, sucrose and starch contents, and α- and β-amylase activities. This treatment also resulted in reduced seed electrical conductivity (EC), hydrogen peroxide (H2O2), and malondialdehyde (MDA) concentrations. The different seed storage conditions had negative effects on germination index, storage compounds, and fatty acids, with the smaller and greater changes under NA and EPPO aging, respectively. During the different aging conditions, it was noted that L. iberica seeds showed greater deterioration compared to L. royleana seeds. In conclusion, post-harvest conditions impact seed quality, with mild stress of the maternal environment increasing the seed longevity of both Lallemantia species.

Genotype-by-Environment Interaction Analysis for Quantity and Quality Traits in Faba Beans Using AMMI, GGE Models, and Stability Indices.

Faba beans are considered one of the most important crops for animal feed. The genotype × environment interaction (GEI) has a considerable effect on faba bean seed production. The objectives of this study included assessing multiple locations and genotypes to understand how various ecosystems and faba bean genotypes relate to one another, and suggesting the ideal climatic conditions, crop management system, and genotypes so that they are carefully chosen for their stability. A 2-year experiment was conducted in order to define the stability across four environments based on stability indices for certain characteristics: moisture (%), ash content (%), crude protein content (%), crude fat (%), total starch (%), and crude fiber content (%). Statistically significant differences indicated that GEIs were present. The heritability was generally high for qualitative traits in comparison with quantitative traits. The crude protein content, plant height, and thousand-seed weight were all positively correlated with the seed yield; however, the other qualitative variables were adversely correlated. The crude protein content of the cultivar Tanagra displayed a high stability index, followed by Ste1. Under conventional management, Tanagra demonstrated high values for the seed yield in Giannitsa and Florina. Ste1 and Ste2 are particularly promising genetic materials that showed high values under low-input conditions. The best genotypes to use and the most favorable environments/types of cultivation were the Tanagra cultivar, followed by the Ste2 genotype, according to the additive main effects and multiplicative interaction (AMMI) and genotype plus genotype-by-environment (GGE) biplot models. Earliness showed significant heritability values and very high stability indices, again indicating qualitative behavior according to genetic parameters. With the exception of the number of pods per plant, which demonstrated low heritability while having excellent index values, traits like seed yield showed relatively low-stability-based heritability values. Global efforts aimed at improving the genetics of faba beans might benefit from genotypes that exhibit consistent yields in various conditions.

In vitro starch digestibility of maize flour and maize extruded noodles based on different particle-size effects

In this study, the particle characteristics of the bimodal distribution of maize flour were utilized to screen maize flour with different grinding degrees. The changes in the digestibility characteristics of maize flour and extruded noodles were compared under the effects of grinding size and screening size. Under the effect of grinding size, the decrease in particle size was accompanied by an increase in the specific surface area and damaged starch contents of maize flour, enhanced the hydration ability of maize flour. And the digestion rate constants of raw flour and cooked flour increased from 0.0278, 0.0646 to 0.0514 and 0.0847, respectively. The digestion rate constant of extruded noodles increased from 0.0088 to 0.0097. Under the effect of screening size, compared to maize large particle flour (LF), small particle flour (SF) had higher total and damaged starch content, higher peak viscosity, and faster starch digestion. However, the digestion rate was lower after cooking. LF contained a higher protein content, and the prepared extruded noodles had thicker edges and a lower digestion rate. Therefore, SF after screening is more suitable for flour products with a low-glycemic index (GI), while LF is more suitable for preparing extruded noodles with a low-GI.

In vitro digestion properties and use of automatic image analysis to assess the quality of wheat bread enriched with whole faba bean (Vicia faba L.) flour and its protein-rich fraction

The trend of incorporating faba bean (Vicia faba L.) in breadmaking has been increasing, but its application is still facing technological difficulties. The objective of this study was to understand the influence of substituting the wheat flour (WF) with 10, 20, 30 and 40 % mass of whole bean flour (FBF) or 10 and 20 % mass of faba bean protein-rich fraction (FBPI) on the quality (volume, specific volume, density, colour, and texture), nutritional composition (total starch, free glucose, and protein contents), and kinetics of in vitro starch and protein digestibility (IVSD and IVPD, respectively) of the breads. Automated image analysis algorithm was developed to quantitatively estimate the changes in the crumb (i.e., air pockets) and crust (i.e., thickness) due to the use of FBF or FBPI as part of the partial substitution of wheat flour. Higher levels of both FBF and FBPI substitution were associated with breads having significant (p < 0.05) lower (specific) volume (at least 25 % reduction) and higher density (up to 35 %), increased brownness (up to 49 % and 78 % for crust and crumb respectively), and up to 2.3-fold increase in hardness. Result from the image analysis has provided useful insights on how FBF and FBPI affecting bread characteristics during baking such as loss of crumb expansion, decrease in air pocket expansion and increase in crust thickness. Overall, incorporation of FBF or FBPI in wheat bread were favourable in reducing the starch content and improving the protein content and IVPD of wheat bread. Since bread remains as a staple food due to its convenience, versatility and affordability for individuals and families on a budget, wheat bread enriched with faba bean could be a perfect food matrix to increase daily protein intake.

Influence of oat flour characteristics on the physicochemical properties of oat-based milk substitutes

This study aimed at investigating the effect of oat composition on the quality characteristics of oat-based milk substitute (OBMS). Raw materials for OBMS consisted of thirty pure cultivar oat flours produced by industrial milling process. The main steps in OBMS preparation included mixing of 10% oat flour with water, starch hydrolysis, solid-liquid separation and formulation of the final product. OBMS was characterised in terms of mass and protein yields, protein content, reducing sugars, particle size, viscosity, dispersion stability and colour. The different composition of oat flours affected the characteristics of the OBMS in terms of mass yield (81.3–88.1%), dry matter yield (56.7–73.8%), protein content (0.63–1.10%), protein yield (31.4–61.6%), content of free reducing sugars (13.1–19.1%), and physical properties including particle size, dispersion stability and viscosity. OBMS mass and dry matter yields correlated positively with both total and damaged starch contents of the oat flour as well as the share of damaged starch of the total starch of the sample, while flour starch content correlated negatively with protein content of OBMS. Protein content of the flour correlated negatively with the mass, dry matter and protein yields and positively with protein content of OBMS. All colour values (L*, a*, b*) of the flour correlated with colour value b* of the OBMS. Protein content and viscosity of OBMS correlated positively with dispersion stability of OBSM. In conclusion, the clear relation between oat composition and the final properties of OBMS suggest relevance of selecting specific oat raw materials to produce good quality OBMS.

Nutritional and functional potentials of germinated rice: A systematic review

The cereal food group contributes significant amounts of the major macronutrients and micronutrients, making it an essential part of a healthy diet. The primary food for nutrition, energy, and nourishment in India, especially in North Eastern India, is rice. It is rich in dietary fiber, vitamin B including niacin, riboflavin, and thiamin, in addition to minerals like phosphorus, potassium, and magnesium. Germination as a biochemical process has the ability to enhance the nutritional value of whole brown rice grains and bioactive properties of rice. It is a time-honored, cost-effective way to prepare sprouted seeds. Since, high molecular proteins break down into low molecular proteins during germination, this process impacts on product qualities including odor, bioactivity and digestibility, which is advantageous for baby nutrition. Varying steeping time or water pH causes changes in reducing sugar, free GABA, and amylase activity, however, there is a decrease in total starch content. Gamma-aminobutyric acid (GABA) inhibits leukemia cell proliferation and stimulates cancer cell Apoptosis. Therefore, the aim of this present review is to highlight the biochemical changes that occur in rice due to germination and its health benefits.

JAZ1 gene regulates starch biosynthesis and changes physicochemical properties in wheat grains

Starch is the main component of crop grains. Jasmonate-ZIM domain (JAZ1), is a transcriptional repressor in the jasmonate signaling pathway, has been widely studied in plant development, and stresses responses. However, its function in crop starch biosynthesis remains unclear. In this study, the intrinsic relationship between TaJAZ1 and starch biosynthesis was studied using barley stripe mosaic virus-induced gene silencing (BSMV-VIGS) method. The results showed that, compared with the control, grain length, thousand kernel weight, contents of total starch and amylopectin were significantly increased in grains of BSMV-TaJAZ1-silenced plants. And its starch ultrastructures, such as volume, surface area, relative crystallinity, and some viscosity parameters were also significantly changed in above grains. Moreover, the molecular mechanisms of TaJAZ1 involving starch biosynthesis were further explored by measuring the expression levels of starch synthesis-related genes. Results showed that TaJAZ1 gene silencing increased the expression of TaAGPS1, TaAGPL1, TaBEIIb and TaSSI and decreased TaGBSSI or TaSSIIIa, while their expressions were separately decreased or increased in TaJAZ1 transiently overexpression wheat plants. To conclude, these findings showed that TaJAZ1 involved starch synthesis by affecting the expression levels of six starch synthesis enzyme-related genes further changing the components, ultrastructures, and physicochemical properties of starch in wheat grain.

A new source of starchy flour: Physicochemical and nutritional properties of starchy kiwifruit flour

The physicochemical and nutritional properties of three starchy kiwifruit flour (SKF) were systematically studied. The results revealed that the total starch content of SKF was 66.63–80.42%. SKF showed a B-type crystal structure with a grain size between 7.08 and 9.02 μm. In comparison to corn starch and potato starch, SKF possessed a lower pH (3.43–4.28), transparency (0.68–1.11%) and setback value (0.20–1.73 Pa·s) and a higher swelling power (9.42–15.02 g/g) and hot paste viscosity (1.73–2.10 Pa·s). Moreover, SFK was rich in protein and various mineral elements. It also contained high levels of total phenolics and exhibited a strong antioxidant capacity. The resistant starch content in SKF was as high as 67.19–73.22%, and the rapidly digestible starch content was remarkably lower than that of corn and potato starch. Overall, these unique physicochemical properties of SKF, coupled with its nutritional benefits, give it a good development potential in the food industry.

The Changes of Phyllosphere Fungal Communities among Three Different Populus spp.

As an ecological index for plants, the diversity and structure of phyllosphere microbial communities play a crucial role in maintaining ecosystem stability and balance; they can affect plant biogeography and ecosystem function by influencing host fitness and function. The phyllosphere microbial communities reflect the immigration, survival, and growth of microbial colonists, which are influenced by various environmental factors and leaves' physical and chemical properties. This study investigated the structure and diversity of phyllosphere fungal communities in three different Populus spp., namely-P. × euramaricana (BF3), P. nigra (N46), and P. alba × P. glandulosa (84K). Leaves' chemical properties were also analyzed to identify the dominant factors affecting the phyllosphere fungal communities. N46 exhibited the highest contents of total nitrogen (Nt), total phosphorus (Pt), soluble sugar, and starch. Additionally, there were significant variations in the abundance, diversity, and composition of phyllosphere fungal communities among the three species: N46 had the highest Chao1 index and observed_species, while 84K had the highest Pielou_e index and Simpson index. Ascomycota and Basidiomycota are the dominant fungal communities at the phylum level. Results from typical correlation analyses indicate that the chemical properties of leaves, especially total phosphorus (Pt), total nitrogen (Nt), and starch content, significantly impact the structure and diversity of the phyllosphere microbial community. However, it is worth noting that even under the same stand conditions, plants from different species have distinct leaf characteristics, proving that the identity of the host species is the critical factor affecting the structure of the phyllosphere fungal community.

Impact of supplement of Qingke flours on physiochemical properties, sensory and in vitro starch digestibility of wheat bread and its enhancement by bread quality improvers.

The aim is to upgrade the formulation to produce wheat bread with lower starch digestibility by supplemented with Qingke flour. Physiochemical properties of multi-scale Qingke flours were examined to select the most satisfied Qingke flour for breadmaking. Data showed multi-scale Qingke samples differed in total starch content, water/oil binding capacity, freeze-thaw stability, but had similar swelling capacity and thermodynamic properties. Addition of Qingke flours significantly reduced the total in vitro starch digestion of bread from 80% to 41% and decreased the rapidly digested starch content from 53% to 27%. However, Qingke flours caused a worse bread quality, texture and sensory e.g. lower bread specific volume (4.26-3.3mL/g), larger hardness (398-1170g) and chewiness (296-707mJ). Meanwhile, hydroxypropyl methylcellulose, sodium stearoyl lactylate and transglutaminase could improve the bread quality and sensory. Lastly, results revealed Qingke-supplemented bread could generate new volatile compounds, hence having a different aroma compared to original wheat bread.

Slow Digestible Starch in Native Pea Starch (Pisum sativum L.) Lowers Glycemic Response with No Adverse Effects on Gastrointestinal Symptoms in Healthy Adults.

Diabetes prevalence achieved 470B in 2021. Diabetics are looking for foods that allow them to better manage the postprandial glycemia. Owing to its large amylose fraction, pea starch may contribute to formulate recipes with a lower glycemic index (GI). This study measured the rapidly, slowly digested and resistant fractions in pea starch and in a powder mix recipe. Starch fractions were determined according to the Englyst methodology. A nonblind repeat measure crossover design trial in healthy humans was used to study the GI of pea starch and maltodextrin powder mix recipes against glucose. Gastrointestinal symptoms were measured. Thirteen healthy volunteers aged 18-60 years with body mass index <30 kg/m2 and fasting blood glucose <6.1 mmol/L participated in the study. They consumed 25 g available carbohydrate portions of the test products. Blood glucose was measured at -5 and 0 min before consumption till 180 min after starting to eat. The slow digestible starch (SDS) content of native pea starch was 30% of the total starch content. The pea-based powder mix recipe contained 25% SDS in comparison with 9% for the maltodextrin-based recipe. The glucose response after pea starch was significantly lower compared with maltodextrin. The glucose response after pea starch recipe was significantly lower compared with maltodextrin recipe. There was no significant difference in mean scores for well-being and gastrointestinal symptoms after consumption of pea starch and maltodextrin or between the two recipes. In conclusion, this study has demonstrated the presence of high SDS content in pea starch, which reduced postprandial glycemic response compared with maltodextrin. The pea starch recipe did not induce any negative gastrointestinal symptoms. Pea starch may, therefore, prove to be a beneficial ingredient in developing food products for improving glycemic control without undesirable side effects.

Compositional characterization of starch, proteins and lipids of long bean, dwarf long bean, mung bean and French bean seed flours

Four underutilized legumes comprised of mung bean, long bean, dwarf long bean and French bean were investigated for their total starch, dietary fibre, amylose, amylopectin and resistant contents along with proteins and lipids profiles employing standard methods in order to explore appropriate end uses. Results showed significant variations (p<0.05) in the fat, protein, moisture, ash, total dietary fibre, carbohydrate, starch, amylose and amylopectin contents of all the four legume seeds Flours. Mung bean, long bean, dwarf long bean, and French bean showed carbohydrates contents of 55.24, 49.63, 48.12 and 45.56 g/100 g, respectively. Dwarf long bean, long bean and mung bean recorded total starch of 38.39, 49.78 and 57.68 g/100 g, respectively. Whereas French bean had the highest total dietary fibre of 16.91 g/100 g and dwarf long bean the highest amylopectin (86.67 g/100 g), both dwarf long bean and long bean recorded insoluble dietary fibre and soluble dietary fibre in the range of 7.25 to 14.58 g/100 g and 0.05 to 1.25 g/100 g, respectively, however, all the seed flours showed higher content of insoluble dietary fibre than soluble dietary fibre. Significant differences (p<0.05) observed in the total starch, resistant starch and non-resistant starch content of all the 4 samples. Non-resistant starch was the predominant constituents of the total of all the seed flours with mung bean showing the highest value (54.16 g/100 g) followed by long bean, dwarf long bean and French bean with 48.74, 37.73 and 16.88 g/100 g, respectively. Though the beans had low amylose contents, their amino acids score and patterns surpassed the FAO reference proteins and their saturated and unsaturated fatty acids ratio falls within FAO allowed limits. This study highlights the hidden potentials of these non-conventional legumes as sources of quality proteins, functional foods, healthy fats and dietary fibres.

Morphological, stomatal, pigmentation, and biomolecular characteristics of a few epiphytic orchid species of India

In order to identify suitable species that can be used for cross-breeding and propagation for horticulture purposes four endemic and epiphytic orchid species, Aerides crispa Lindl., A. maculosa Lindl., A. ringens Fischer. and A. odorata Lour. were studied by comparing their leaf morphology, stomata, pigmentation, and biomolecules. Standard methods were used for the evaluation. A. odoratum, native to the lowest altitude, was characterized by thin, long leaves with the lowest specific leaf area and higher water content. Among the four species studied, stomata were bigger in size and less in number in A. odoratum. Maximum total soluble sugars, soluble proteins, amino acids, and starch contents, an indicator of a better photosynthesis rate were noted in A. odoratum. Total chlorophyll and carotenoid contents per unit leaf area were higher in A. odoratum and A. ringens. Our results concluded that variation in environmental temperature, humidity, sunlight intensity, and exposure of orchids at different altitudes may cause alteration in traits that can be inherited over a period.

Effect of Planting Density on the Nutritional Quality of Grain in Representative High-Yielding Maize Varieties from Different Eras

Maize is essential in ensuring food security in China as a primary food and feed crop. One of the main ways to increase yield in maize production systems is to increase planting density as appropriate. Clarifying the relationship between planting density and grain nutritional quality can provide theoretical guidance for high-yielding high-quality maize cultivation and management practices. To this end, five representative high-yielding maize varieties from the 1970s to the 2010s in China were used as experimental material, and two planting densities of 45,000 plants hm−2 and 105,000 plants hm−2 were set to analyze the changing patterns of yield traits and grain nutrient quality of maize varieties in different eras, as well as their responses to densification conditions. The results showed that, under low-density conditions, the grain nutrient quality components of the 2010s’ variety (DH618) were all different 75 days after anthesis compared with the 1970s’–2000s’ varieties and yields also significantly increased by 11.15% to 19.18% (p &lt; 0.05). The increase in planting density led to a rise in total grain starch and soluble sugar content 75 days post-anthesis in all varieties from the 1970s to the 2010s, with increases of 0.65–1.65% and 39.44–69.01%, and a decrease in crude grain protein and crude fat content, with reductions of 4.15–8.50% and 3.00–11.18%. The increase in total grain starch content 75 days post-anthesis was mainly due to the rise in grain starch accumulation between 23 and 47 days post-anthesis in the 1970s’–2010s’ varieties, with an increase of 7.72–9.19% in all varieties. The higher accumulation of crude fat and soluble sugar in the 0–23 days post-anthesis period also contributed to the increase in total starch accumulation in the 23–47 days post-anthesis period. Ultimately, densification conditions also contributed to a significant increase in yield across all eras of the varieties based on changes in grain nutritional quality, with a more significant increase in yield due to densification and a smaller decrease in grain crude fat content due to densification 75 days after anthesis in the 2010s’ variety (DH618). Therefore, in cultivation and production processes that do not have specific requirements for the nutritional quality components of maize grain, we suggest that the use of a representative high-yielding maize variety (DH618) from the 2010s, together with appropriate planting at close planting distances, can significantly increase maize yields based on an increase in the total starch content of the grain at physiological maturity.

Spermidine enhances heat tolerance of rice seeds during mid-filling stage and promote subsequent seed germination.

Heat stress is a vital factor which restricts rice seed quality and yield. However, the response mechanism to heat stress in the mid filling stage of rice seed is unclear. In the present study we integrated phenotypic analysis with biochemical, hormone, and gene expression analysis in order to explore technologies for improving rice seeds heat tolerance and subsequent seed germination. Spermidine (Spd) application effectively alleviated the damage of heat stress treatment during mid-filling stage (HTM, 12-20 days after pollination) on seed development, promoted subsequent seed germination and seedlings establishment. Spd significantly increased seed dry weight, starch and amylose contents during seed development under heat stress, and improved seed germinate, seedlings establishment and seedling characteristics during germination time. Biochemical analysis indicated that, HTM significantly decreased the activities of several starch synthase enzymes and led to a decrease in starch content. While Spd treatment significantly enhanced the activities of ADP-glucose pyrophosphorylas and granule-bound starch synthase, as well as the corresponding-genes expressions in HTM rice seeds, resulting in the increases of amylose and total starch contents. In addition, Spd significantly increased the catalase and glutathione reductase activities together with corresponding-genes expressions, and lowered the overaccumulation of H2O2 and malondialdehyde in HTM seeds. In the subsequent seed germination process, HTM+Spd seeds exhibited dramatically up-regulated levels of soluble sugars, glucose, ATP and energy charges. Consistently, HTM+Spd seeds showed significantly increased of α-amylose and α-glucosidase activities as well as corresponding-genes expressions during early germination. Moreover, HTM evidently increased the abscisic acid (ABA) content, decreased the gibberellin (GA) content, and accordingly significantly declined the GA/ABA ratio during early rice seeds germination. However, Spd treatment did not significantly affect the metabolism of GA and ABA in seed germination stage. The present study suggested that Spd treatment could effectively alleviate the negative impact of HTM on seed development and the subsequent seed germination, which might be closely correlated with starch synthesis and antioxidant defense during seed filling period, starch decomposition and energy supply in seed germination period.