Fruit Set Rate Research Articles

The Pitaya Flower Tissue's Gene Differential Expression Analysis between Self-Incompatible and Self-Compatible Varieties for the Identification of Genes Involved in Self-Incompatibility Regulation.

Self-incompatible pitaya varieties have low fruit-setting rates under natural conditions, leading to higher production costs and hindering industrial prosperity. Through transcriptome sequencing, we obtained the 36,900 longest transcripts (including 9167 new transcripts) from 60 samples of flowers. Samples were collected pre- and post-pollination (at 0 h, 0.5 h, 2 h, 4 h, and 12 h) from two varieties of pitaya (self-compatible Jindu No. 1 and self-incompatible Cu Sha). Using the RNA-Seq data and comparison of reference genomes, we annotated 28,817 genes in various databases, and 1740 genes were optimized in their structure for annotation. There were significant differences in the expression of differentially expressed genes (DEGs) in the pitaya stigmas under different pollination types, especially at the late post-pollination stage, where the expression of protease genes increasedal significantly under cross-pollination. We identified DEGs involved in the ribosomal, ubiquitination-mediated, and phyto-signaling pathways that may be involved in pitaya SI regulation. Based on the available transcriptome data and bioinformatics analysis, we tentatively identified HuS-RNase2 as a candidate gynogenetic S gene in the pitaya GSI system.

Determination of Breeding Performance on Halfeti Rose (R. odorata Louis XIV) In Crossbreeding

One of the factors influencing rose crossbreeding success is parental selection. The success rate of a breeder is influenced by factors such as ploidy level, pollen quality, seed number per fruit, and seed germination rate, which indicate parental productivity. This study was conducted to determine the productivity of Halfeti Rose (Rosa odorata Louis XIV) as a seed parent and its compatibility with the commercial rose varieties in terms of combination. Six commercial-cut roses (Inferno, Moonlight, Tineke, Black Baccara, Lady Rose, Speelwark) were used as pollen parents. Fruit set rate, seed number per fruit, seed and fruit weight, seed germination rate, and pollen germination rate were recorded. Among the commercial-cut roses, the pollen germination rate ranged from 7.82% to 23.55%. The highest pollen germination rate was observed in the Tineke and Black Baccara varieties, respectively. The fruit set rate of combinations where Halfeti Rose was used as the seed parent was determined as 63.75%, the number of seeds per fruit was 5.05, and the seed germination rate was 31.21%. Based on PCA and Heatmap analysis, Halfeti x Speelwark, Halfeti x Black Baccara, and Halfeti, x Lady Rose were found to be the most successful combinations. Halfeti Rose exhibited values close to the overall average in terms of fruit set rate and seed germination rate among rose breeding studies. The parameters mentioned in studies on rose breeding show that the Halfeti rose has the potential to be used as a seed parent.

Influence of Mechanical Flower Thinning on Fruit Set and Quality of ‘Arisoo’ and ‘Fuji’ Apples

This study aimed to identify the efficiency of mechanical flower thinning (MFT) and its influence on apple fruit quality. In the first experiment, ‘Arisoo’ apple flowers were subjected to MFT with one hundred sixty-two (half) and three hundred twenty-four (full) strings at the same rotor (300 rpm) and tractor (6 km/h) speeds. Hand thinning was performed as a control. The number of removed flowers in each terminal and lateral flower cluster was slightly higher in MFT with full-strings than that of MFT with half-strings. The fruit set rate was lower in MFT with full-strings than that of MFT with half-strings. However, the use of full-strings during mechanical thinning increased the leaf damage rate compared to half-strings. Except a* value, MFT with full-strings improved flesh firmness, soluble solids content (SSC) and titratable acidity (TA), and reduced starch pattern index of fruits at harvest compared to the control. In the second experiment, ‘Fuji’ apple flowers were subjected to chemical thinning, MFT (300 rpm, 6 km/h), and MFT + chemical thinning treatments and compared with hand thinning (control). The thinning efficiency of MFT was similar to that of chemical thinning and MFT + chemical thinning treatments in terms of the removal of flowers and fruit set rates. Compared to the control, MFT, chemical thinning, and their combined treatments improved flesh firmness and SSC of fruits at harvest. TA was highest in the chemical thinning treatment compared to other thinning treatments. However, fruit size, weight, and a* value were unaffected by any treatment. In conclusion, the use of full-strings during MFT achieved optimal results in ‘Arisoo’ apples. In ‘Fuji’ apples, MFT treatment alone achieved effective results and the addition of chemical thinning after MFT had no supportive role in thinning efficiency and fruit quality.

Effects of Low Temperature on Pedicel Abscission and Auxin Synthesis Key Genes of Tomato.

Cold stress usually causes the abscission of floral organs and a decline in fruit setting rate, seriously reducing tomato yield. Auxin is one of the key hormones that affects the abscission of plant floral organs; the YUCCA (YUC) family is a key gene in the auxin biosynthesis pathway, but there are few research reports on the abscission of tomato flower organs. This experiment found that, under low temperature stress, the expression of auxin synthesis genes increased in stamens but decreased in pistils. Low temperature treatment decreased pollen vigor and pollen germination rate. Low night temperature reduced the tomato fruit setting rate and led to parthenocarpy, and the treatment effect was most obvious in the early stage of tomato pollen development. The abscission rate of tomato pTRV-Slfzy3 and pTRV-Slfzy5 silenced plants was higher than that of the control, which is the key auxin synthesis gene affecting the abscission rate. The expression of Solyc07g043580 was down-regulated after low night temperature treatment. Solyc07g043580 encodes the bHLH-type transcription factor SlPIF4. It has been reported that PIF4 regulates the expression of auxin synthesis and synthesis genes, and is a key protein in the interaction between low temperature stress and light in regulating plant development.

A female fertile triploid loquat line produces fruits with less seed and aneuploid germplasm

Most loquat cultivars are diploid (2n=2x=34) and produce numerous large seeds, affecting their edibility rate and processing. Therefore, breeding less seed triploid cultivars has always been a primary goal of loquat breeding. However, most triploid plants have low fertility and cannot meet commercial needs. Here, we identified a triploid line, Q24, that can set seeds normally under natural conditions. We statistically analyzed the fruit setting rate, seed number, and external quality of Q24. The fruit setting rate of Q24 was similar to that of diploid Q14. The number of seeds in Q24 was 79.40% less than that in Q14. Pollen viability analysis and hybridization experiments revealed that Q24 male gametes were sterile. Further cytological observations showed that male gamete sterility was caused by abnormal chromosome pairing during meiosis. Hybridization experiments also confirmed that Q24 female gametes were fertile. Finally, chromosome counts showed that the progeny of Q24 could produce aneuploids at a frequency of 92.52%. In conclusion, the triploid Q24 loquat is a valuable breeding resource, not only because it has less seed and fertile female gametes but also because most of its offspring are aneuploids. This study provides an optimal material for breeding the less seed loquat, and its large number of aneuploid progenies enrich the germplasm resources of loquat.

The Pollen Donor Affects Seed Development, Taste, and Flavor Quality in 'Hayward' Kiwifruit.

To investigate how different species or ploidy level of pollen donors affects the fruit quality of kiwifruit, flowers of 'Hayward' kiwifruit (a hexaploid Actinidia deliciosa cultivar, 6x) were hand-pollinated with pollen from ten different male donors. Kiwifruit plants pollinated with four distant species-M7 (2x, A. kolomikta), M8 (4x, A. arguta), M9 (4x, A. melanandra), and M10 (2x, A. eriantha)-had a low fruit-setting rate and therefore were not investigated further. Of the other six treatments, kiwifruit plants pollinated with M4 (4x, A. chinensis), M5 (6x, A. deliciosa) M6 (6x, A. deliciosa) had a larger fruit size and weight than those pollinated with M1 (2x, A. chinensis) and M2 (2x, A. chinensis). However, pollination with M1 (2x) and M2 (2x) resulted in seedless fruits, having few small and aborted seeds. Notably, these seedless fruits had higher fructose, glucose, and total sugar and lower citric acid content. This resulted in a higher sugar to acid ratio compared to fruits from plants pollinated with M3 (4x, A. chinensis), M4 (4x), M5 (6x), and M6 (6x). Most volatile compounds increased in the M1 (2x)- and M2 (2x)-pollinated fruit. A combination of principal component analysis (PCA), electronic tongue, and electronic nose suggested that the different pollen donors significantly affected the kiwifruit's overall taste and volatiles. Specifically, two diploid donors had the most positive contribution. This was in agreement with the findings from the sensory evaluation. In conclusion, the present study showed that the pollen donor affected the seed development, taste, and flavor quality of 'Hayward' kiwifruit. This provides useful information for improving the fruit quality and breeding of seedless kiwifruit.

Cross-Compatibility in Interspecific Hybridization of Different Curcuma Accessions.

Curcuma is extensively cultivated as a medicinal and ornamental plant in tropical and subtropical regions. Due to the bright bract color, distinctive inflorescence and long blooming period, it has become a new favorite in terms of the urban landscape, potted flowers and cut flowers. However, little research on breeding new cultivars using traditional plant breeding methods is available on the genus Curcuma. In the present study, pollen viability and stigma receptivity evaluation were performed, and the genetic relationship of 38 Curcuma accessions was evaluated, then 5 C. alismatifolia Gagnep. (Ca), 2 C. hybrid (Ch), 2 C. sparganiifolia Gagnep. cultivars and 4 Curcuma native species were selected as parents for subsequent interspecific cross-breeding. A total of 132 reciprocal crosses were carried out for interspecific hybridization, including 70 obverse and 62 inverse crosses. Obvious discrepancies among fruit-setting rates were manifested in different combinations and in reciprocal crosses. Results showed that the highest fruit-setting rate (87.5%) was observed in the Ca combinations. There were 87 combinations with a fruit-setting rate of 0%, which meant nearly 65.9% was incompatible. We concluded that C. alismatifolia 'Siam Shadow' (Ch34) was suitable as a male parent and C. petiolata Roxb. (Cpet) was suitable as a female parent to improve the fruit-setting rates. The maximum number of seeds per fruit (45.4) was obtained when C. alismatifolia 'Chiang Mai Pink' (Ca01) was used as a female parent followed by C. attenuata Wall. ex Baker (Catt) (42.8) and C. alismatifolia 'Splash' (Ca63) (39.6) as male parents. The highest germination rate was observed for the Ca group followed by Catt and C. sparganiifolia 'Maetang Sunrise' (Csms). The germination rates of Ca accessions ranged from 58.2% (C. alismatifolia 'Siam Scarlet' (Ca06) as a male parent) to 89.3% (C. alismatifolia 'Sitone' (Ca10) as a male parent) with an average value of 74.0%. Based on the results of hybrid identification, all the individuals from the four combinations exhibited paternal-specific bands, indicating that the true hybrid rates of crossings were 100%. Our results would facilitate the interspecific hybridization and introduction of genetic variation from wild species into the cultivars in Curcuma in the future, which could be helpful in realizing the sustainable application in urban green areas.

Evaluation of Growth and Pollen Viability (Fertility) in Relation to Fruit Set among Five Varieties of Tomato

The evaluation of pollen viability and fruit setting capacity are two essential criteria for pollinator’s characterization. This study was carried out to evaluate pollen Fertility/ viability in five Varieties of Tomatoes. We analyzed the viability of pollen grains of five different varieties of tomatoes grown in ITM University, Gwalior, Madhya Pradesh, India. Aceto- carmine method is used to estimate pollen viability. The germination percentage, pollen viability and Fruit setting rate were recorded at different stages respectively. Pollen viability in relation to fruit set was analyzed while growth parameters and fruit yield per plant of each variety were also collected and analyzed. Results displayed that the highest pollen viability rate (100%) was obtained in SWEAKAR-448 Variety followed by Arka Vikas (95%), ARJUN-135 (93%), 9005-SIRI (90%) and PKM-1 (80%). The highest percentage of germination (95%) was shown by 9005-SIRI Variety and maximum fruit setting (15-20 Fruits per plant) was recorded in the SWEAKAR-448 Variety. The results showed significant vegetative growth variations and correlations between pollen viability and fruit setting characters. In addition, it was found a noticeable variation in Pollen viability/fertility, was not proportional to fruit setting percentage. In general Pollen viability was directly linked to fruit set, whereas formation and fruit set were not in the tomato varieties that were investigated. Pollen viability was high, which was accompanied through a reduction in the number of fruit sets, fruit size and pollen viability in the field is highly variable, indicating that differences in microenvironment may have a profound effect on fruit setting and pollen viability.

Investigation of self-productivity in some olive cultivars grown under Antalya ecological conditions

Irregular fruit yield in olives is caused by ecology, cultural processes as well as self-inefficiency and not choosing suitable pollinators. Since the self-productivity of olive varieties in different growing areas, this research was carried out to determine the productivity of 'Gemlik', 'Manzanilla', 'Memecik', 'Nizip Yağlık' and 'Tavşan Yüreği' with high commercial value. Selfing and natural pollination were determined in the Akdeniz University Faculty of Agriculture Research and Application Field in Antalya. In self-pollination, the flowers on the clusters were placed into cloth bags at the balloon stage, the pollen was poured into the pouch at the time of flowering, the pouch mouth was closed with a rope and the pouch was shaken to pollinate. Significant differences were determined in % fruit set rates obtained in varieties as a result of selfing and natural pollination. In all olive cultivars used in the experiment, the percentage of fruit obtained from free pollination was higher than self-pollination. 'Gemlik' and ‘Tavşan Yüreği' were found to be self-fertile, 'Memecik' and 'Nizip Yağlık' were found to be partially productive, and 'Manzanilla' were found to be self-inefficient. The highest fruit set in both free and selfing was determined in the 'Tavşan Yüreği' cultivar.

A novel pollination robot for kiwifruit flower based on preferential flowers selection and precisely target

Manual pollination of kiwifruit flowers is a labor-intensive work that is highly desired to be replaced by mechanical/robotic operations. In this application note, a pollination robot was developed for achieving precision pollination of kiwifruit flowers in orchard. The pollination robot consists of five systems include vision system, air–liquid spray system, mechanical arm, crawler-type chassis, and control system, which could select suitable flowers and then target to their pistil for precision pollination. Field experiments were conducted in a commercial kiwifruit orchard to evaluate its feasibility and performance, which achieved an average pollination success rate of 99.3% with an average fruit set rate of 88.5%. Furthermore, compared to artificial assisted pollination methods, it could improve utilization rate of kiwifruit pollen with an average consumption of 0.15 g in 60 flowers. The validations demonstrated that this pollination robot could achieve efficient pollination for kiwifruit flowers and save pollen.

Enrichment of high‐purity nervonic acid ethyl ester from Acer truncatumBunge seed oil by combination method of urea inclusion and molecular distillation

AbstractAcer truncatum Bunge is a type of maple that is unique to China. Its fruit setting rate and seed oil content are both high. The oil is mainly composed of C16–C24 fatty acids and contains 5%–7% nervonic acid (NA). NA and its derivatives can delay ageing and prevent and treat disorders such as senile dementia and Alzheimer's disease. The content of NA ethyl ester prepared by the seed oil of A. truncatum Bunge is 5.84%. We report a new process for the enrichment of NA ethyl ester by urea inclusion (UI) and molecular distillation (MD), with the aim of obtaining highly pure NA ethyl ester. First, based on the difference in fatty acid ethyl ester saturation and carbon chain length, unwanted compounds such as oleic acid ethyl ester, linoleic acid ethyl ester, and sterol were removed by one‐stage UI, the content of NA ethyl ester was increased to 18.69%. The oil in the UI compound was used as a feed, and differences in the mean molecular free paths between the components were exploited to separate the C16–C20 fatty acid ethyl esters (FAEEs) by two‐stage MD. The total content of C16–C20 FAEEs decreased to 3.69% and the purity of NA ethyl ester increased to 47.47%. A new purification process of UI‐MD‐UI was established and NA ethyl ester could be purified to 91.8%. The combination of MD and UI has an important reference value for the industrialization of producing high‐purity NA ethyl ester.

Potential Gene Flow Between <i>Gossypium hirsitum</i> and <i>Abelmoschus esculentus</i> Through Interspecific Hybridization

The introduction of transgenic varieties of cotton (<i>Gossypium hirsitum</i>) in Cameroon has posed numerous concerns. One of the most concern was the horizontal transfer of the <i>Bt</i> gene to related species such as <i>Abelmoschus esculentus</i>. The current study was conducted to assess the occurrence <i>Bt</i> gene transfer from <i>Gossypium hirsitum </i>to<i> Abelmoschus esculentus</i>. To achieve this, the stigma receptivity periods and the viability of pollen grains were evaluated. The fruit set rates of 675 controlled intra- and interspecific crosses were assessed. The results showed that stigma receptivity and pollen grain viability are optimal at anthesis in both species, with a longer duration over 24 hours in <i>G. hirsitum</i>. Intra-specific crosses within the two species have shown fruit set rates of nearly 60-80%. Interspecific crosses gave a fruit set rate close to 2%, especially when <i>A. esculentus</i> is used as the female parent, and zero results in reciprocal crosses. The finding of the study pointed out that the possibility of horizontal transfer of a transgene to cotton relatives. In future studies, it would be useful to monitor the fate of seeds from interspecific crosses between both species and assess the agro-morphological and molecular characteristics of these possible hybrids.

Climatic Factor Differences and Mangosteen Fruit Quality between On- and Off-Season Productions

The objective of this study was to investigate the differences in climatic factors and fruit quality between on- and off-season production periods. Climate, soil, and mangosteen measurements were all studied during on- and off-season production. We chose 40 mangosteen trees and observed flowering and fruit set rates over two production periods. The results showed that the number of flowers per branch, the number of fruits per branch, the circumference of fruits, and the fruit weight were higher during the on-season mangosteen production period than during the off-season mangosteen production period. However, the number of edible pulp segments, peel thickness, percentage of translucent flesh, and fruit gumminess were lower in the on-season mangosteen production period than in the off-season mangosteen production period. The percentage of fruit scars did not differ between the on- and off-season mangosteen production periods. When compared to the on-season mangosteen production period, there was lower relative humidity, soil moisture at 120 cm depth, and leaf wetness at 15 cm above ground during the off-season mangosteen production period; however, there was higher air temperature, soil moisture, and soil temperature at all four depth levels. Doi: 10.28991/ESJ-2023-07-02-020 Full Text: PDF

Differences in flowering phenology and seed production of four morning glory (Ipomoea) species in Japan

AbstractThe spread of morning glory (Ipomoea spp.) in soybean fields in Japan has severely decreased soybean yield. Yet, current control measures do not control the proliferation of Ipomoea spp. As little is known about the flowering period and seed production among the different invading Ipomoea spp., it is challenging to create targeted control measures based on ecological characteristics. This study aimed to reveal the characteristics of the flowering phenology and seed production of four morning glory species, namely, Ipomoea coccinea L. (red morning glory), Ipomoea lacunosa L. (pitted morning glory), Ipomoea hederacea L. Jacq. var. integriuscula A. Gray (entireleaf morning glory), and Ipomoea triloba L. (three‐lobe morning glory). Between 2017 and 2019, the four selected study species were grown under similar conditions of soil quality, irrigation, and environmental influences and their flowering phenology and seed data were recorded. The flowering period ranged from 36 to 40 days, and the initial flowering of I. triloba was approximately 2 weeks later than the others. I. coccinea had the highest flowering number and seed production, followed by I. lacunosa, I. triloba, and I. hederacea var. integriuscula. The fruit setting rate of I. triloba decreased later in the reproductive stage but tended to increase as the daily mean temperature increased on each flowering day. Thus, we report that the flowering phenology and seed production differed greatly among the Ipomoea spp. These findings can provide crucial insights into designing targeted species‐specific control measures against the spread of Ipomoea spp. in Japan.

Differential gene expression analysis and physiological response characteristics of passion fruit (Passiflora edulis) buds under high-temperature stress.

High temperature in summer is an unfavorable factor for passion fruit (Passiflora edulis), which can lead to restricted growth, short flowering period, few flower buds, low fruit setting rate, severe fruit drop, and more deformed fruit. To explore the molecular physiology mechanism of passion fruit responding to high-temperature stress, we use 'Zhuangxiang Mibao', a hybrid passion fruit cultivar, as the test material. Several physiological indicators were measured and compared between high-temperature (average temperature 38 °C) and normal temperature (average temperature 25 °C) conditions, including photosynthesis, chlorophyll fluorescence parameters, peroxidase activity (POD), superoxide dismutase activity (SOD) and malondialdehyde content. We performed RNA-seq analysis combined with biochemistry experiment to investigate the gene and molecular pathways that respond to high-temperature stress. The results showed that some physiological indicators in the high-temperature group, including the net photosynthetic rate, stomatal conductance, intercellular CO2 concentration, transpiration rate, and the maximum chemical quantum yield of photosystemII (PSII), were significantly lower than those of the control group. Malondialdehyde content was substantially higher than the control group, while superoxide dismutase and superoxide dismutase activities decreased to different degrees. Transcriptome sequencing analysis showed that 140 genes were up-regulated and 75 genes were down-regulated under high-temperature stress. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) annotation analysis of differentially expressed genes revealed many metabolic pathways related to high-temperature stress. Further investigation revealed that 30 genes might be related to high-temperature stress, such as chlorophyllide a oxygenase (CAO), glutathione (GSH), WRKY transcription factors (WRKY), and heat shock protein (HSP), which have also been reported in other species. The results of real-time fluorescence quantitative PCR and RNA-seq of randomly selected ten genes are consistent, which suggests that the transcriptome sequencing results were reliable. Our study provides a theoretical basis for the mechanism of passion fruit response to high-temperature stress. Also, it gives a theoretical basis for the subsequent breeding of new heat-resistant passion fruit varieties.

Combined analysis of multi-omics reveals the potential mechanism of flower color and aroma formation in Macadamia integrifolia.

Macadamia integrifolia Maiden & Betche is a domesticated high-value nut crop. The development of nut flower affects the fruit setting rate, yield and quality of nuts. Therefore, in this experiment, two varieties with different flower color, flowering time, flowering quantity and nut yield (single fruit weight) were selected as the research objects. Transcriptome (RNA-Seq) and metabolome (LC-MS/MS, GC-MS) analyses were performed to study the regulatory mechanisms of nut flower development, color and aroma. The results indicated that plant hormone signal transduction, starch sucrose metabolism, phenylpropanoid metabolism, flavonoid biosynthesis, and anthocyanin biosynthesis pathways were related to nut flower development and flower color formation. In the early stage of flowering, most of the differentially expressed genes (DEGs) are involved in the IAA signal transduction pathway, while in the later stage, the brassinolide signal pathway is mainly involved. In starch and sugar metabolism, DEGs are mainly involved in regulating and hydrolyzing stored starch into small molecular sugars in flower tissues. In the phenylpropanoid biosynthesis pathway, DEGs are mainly related to the color and aroma (volatile organic compounds, VOCs) formation of nut flowers. Four color formation metabolites (anthocyanins) in nut flowers were found by LC-MS/MS detection. In addition, the VOCs showed no significant difference between red nut flowers (R) and white nut flowers (W), which was mainly reflected in the aroma formation stage (flowering time). And 12 common differentially accumulation metabolites (DAMs) were detected by GC-MS and LC-MS/MS. At the same time, the DEGs, AAT, LOX and PAL genes, were also identified to regulate key metabolite synthesis during nut flower development. These genes were further verified by qRT-PCR. Our results provide insights to clarify the molecular mechanism of color and aroma formation during M. integrifolia flower development that pave the way for nut quality and yield breeding.

Swallowtail butterflies and hawkmoths contribute equally to the pollination of Habenaria dentata (Orchidaceae)

Mixed pollination system with both diurnal and nocturnal visitors contributing to pollen transfer and seed set have been documented in many angiosperm species. The flowers of Habenaria species are usually green or white, with a long nectar secreting spur, and are usually interpreted as specialized for pollination by nocturnal moths. With a few exceptions, nocturnal moths and diurnal butterflies are both reported as pollinators of Habenaria species. However, the relative contributions made by moths versus butterflies to the reproductive success in the same orchid species has rarely been studied. We investigated the floral morphology, pollinators, pollination efficiency, and breeding system of Habenaria dentata in southern China. We showed that two species of diurnal swallowtail butterflies (Papilio helenus and Papilio memnon) and a species of crepuscular hawkmoth (Eupanacra mydon) were this orchid's effective pollinators. The pollinaria were attached to the eyes of these three insect species. Pollinator exclusion experiments showed that pollinarium removal and pollinium deposition rates on stigmas by butterflies (47.51% and 38.64%, respectively) were not significantly different from those made by hawkmoths (50.70% and 34.47%, respectively), indicating that diurnal and crepuscular visits contributed equally to reproductive success. As natural rates of insect-mediated pollination of our population of H. dentata resulted in fruit set rates of 93.33%, rejected the prospect that this population was pollinator limited. Hand pollination experiments indicated that H. dentata was self-compatible but without autonomous self-pollination. The proportion of well-developed seeds with large embryos in self-pollinated fruits was significantly lower than in cross-pollinated fruits, suggesting natural selection favors xenogamy. Our results highlighted the importance of both butterflies and hawkmoths contributing to the reproductive success of a rare orchid with a mixed pollination system.

Gene coexpression analysis reveals key pathways and hub genes related to late-acting self-incompatibility in Camellia oleifera.

Self-incompatibility (SI) is an important strategy for plants to maintain abundant variation to enhance their adaptability to the environment. Camellia oleifera is one of the most important woody oil plants and is widely cultivated in China. Late acting self-incompatibility (LSI) in C. oleifera results in a relatively poor fruit yield in the natural state, and understanding of the LSI mechanism remains limited. To better understand the molecular expression and gene coexpression network in the LSI reaction in C. oleifera, we conducted self- and cross-pollination experiments at two different flower bud developmental stages (3-4 d before flowering and 1 d before flowering), and cytological observation, fruit setting rate (FSR) investigation and RNA-Seq analysis were performed to investigate the mechanism of the male -female interaction and identify hub genes responsible for the LSI in C. oleifera. Based on the 21 ovary transcriptomes, a total of 7669 DEGs were identified after filtering out low-expression genes. Weighted gene coexpression network analysis (WGCNA) divided the DEGs into 15 modules. Genes in the blue module (1163 genes) were positively correlated with FSR, and genes in the pink module (339 genes) were negatively correlated with FSR. KEGG analysis indicated that flavonoid biosynthesis, plant MAPK signaling pathways, ubiquitin-mediated proteolysis, and plant-pathogen interaction were the crucial pathways for the LSI reaction. Fifty four transcription factors (TFs) were obtained in the two key modules, and WRKY and MYB were potentially involved in the LSI reaction in C. oleifera. Network establishment indicated that genes encoding G-type lectin S-receptor-like serine (lecRLK), isoflavone 3'-hydroxylase-like (CYP81Q32), cytochrome P450 87A3-like (CYP87A3), and probable calcium-binding protein (CML41) were the hub genes that positively responded to the LSI reaction. The other DEGs inside the two modules, including protein RALF-like 10 (RALF), F-box and pectin acetylesterase (MTERF5), might also play vital roles in the LSI reaction in C. oleifera. Overall, our study provides a meaningful resource for gene network studies of the LSI reaction process and subsequent analyses of pollen-pistil interactions and TF roles in the LSI reaction, and it also provides new insights for exploring the mechanisms of the LSI response.

Weather conditions affect pollinator activity, fruit set rate, and yield in Japanese apricot

Japanese apricot blooms in mid-winter, and thus severe weather conditions, including low temperatures, sometimes limit pollinator activity and consequently decrease fruit set rate and yield. Plant physiology is also affected by weather conditions. In this study, we aimed to evaluate the effect of pollinator activity on fruit set rate and yield, in comparison with the effects of meteorological factors. First, we conducted field experiments in 2021 and 2022 at Wakayama prefecture. The results showed that honey bee visitation increased as ambient temperature increased. Fruit set rate also increased under warm conditions when Japanese apricot was naturally pollinated by honey bees. In contrast, hand-pollinated flowers were not affected by ambient temperature. These results revealed that low temperature during the flowering period decreased pollinator visitation but did not affect plant fertilization ability. To compare pollinator activity with meteorological factors over a long period, including the pre- and post-flowering periods, we used a state-space model describing the time series of fruit set rate. The model using fruit set rate data and meteorological records over 15 years (2007–2021) at the Japanese Apricot Laboratory showed that the pre-blossom temperature and number of days suitable for pollination significantly affected the fruit set rate. Another model for the time series of fruit yield using the fruit yield records over 46 years (1976–2021) in Wakayama prefecture showed that fruit yield was affected by number of suitable pollination days, pre-blossom temperature, and sunshine duration before harvest. Moreover, the introduction of Western honey bees into orchards had considerable effects on fruit yield. These results indicate that pollinator activity (which is responsive to weather conditions) and pre-blossom temperature have a significant influence on fruit set rate and yield in Japanese apricot.

甜樱桃对高温胁迫的生理响应

PDF HTML阅读 XML下载 导出引用 引用提醒 甜樱桃对高温胁迫的生理响应 DOI: 10.5846/stxb202103230764 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 浙江省科技厅公益技术研究项目（LGN21C150005）；杭州市农科院科技推广项目（2019HNCT-26） Physiological responses to high temperature stress in Prunus avium L. Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:为探讨甜樱桃对高温胁迫的响应机制，以1年生的甜樱桃嫁接盆栽苗为试材，研究了自然高温处理及胁迫后恢复对其叶片生理和超显微结构的影响。结果表明：经连续3d日最高气温均值达57.7℃胁迫后，甜樱桃叶片过氧化氢酶（CAT）和抗坏血酸过氧化物酶（APX）活性、超氧阴离子（O2·-）产生速率、非光化学淬灭系数（qN）显著增加，渗透调节物质可溶性蛋白、可溶性糖及脯氨酸含量显著提高，谷胱甘肽还原酶（GR）活性、叶绿素含量、PSII最大光化学效率（Fv/Fm）和电子传递速率（ETR）显著下降，超氧化物歧化酶（SOD）和过氧化物酶（POD）活性及光化学淬灭系数（qP）变化不显著。同时对叶片显超微结构观察发现，胁迫引起叶绿体变性，基质内囊体发生扭曲，部分基粒类囊体片层消失，出现大量巨型淀粉粒及嗜锇颗粒。恢复2d后SOD、POD、CAT、APX活性以及可溶性糖、可溶性蛋白、叶绿素总含量均显著下降，而GR活性和脯氨酸含量显著升高。以上表明，连续3d自然最高气温达57.7℃对甜樱桃叶片抗氧化系统和光合特性等产生了显著影响，叶绿体超显微结构受到明显破坏，对叶片造成了不可逆伤害。 Abstract:Sweet cherry is the earliest fruit ripen tree in north China and mainly cultivated in Taian, Yantai and Dalian. In recent years, due to the early rise of spring temperature in south China and the rapid development of leisure and sightseeing agriculture, sweet cherry had gradually developed to the south. However, high temperature was more frequent in south China in summer. The influence of temperature on plant are various, which can lead to reactive oxygen species (ROS) in a large number of accumulation in plants and the stability of the biofilm fall and the permeability increases, large molecules such as proteins and nucleic acids, DNA rupture, enzymatic reaction efficiency drops, organelles such as chloroplasts and mitochondria structure was damaged and photosynthetic rate decreased significantly, growth and development, Eventually, the yield and quality of plants were severely reduced. Meanwhile high temperature was closely related to the double pistil rate of sweet cherry. The fruit setting rate of sweet cherry was affected, especially the commercial fruit rate. High temperature became a limiting factor for the southward development of sweet cherry. To investigate the response mechanism of sweet cherry to high temperature stress, the effects of natural high temperature treatment and stress recovery on physiological indexes and ultrastructure of grafted pot seedlings of 1-year sweet cherry were studied in this research. After the seedlings were treated at the average maximum temperature 57.7℃ in consecutive 3 days, the catalase (CAT) and ascorbic peroxidase (APX) activity, superoxide anion (O2·-) producing rate and coefficient of the photochemical quenching (qN) increased significantly in sweet cherry leaves. The osmotic regulation substances including soluble protein, soluble sugar and proline content increased significantly. The glutathione reductase (GR) activity, chlorophyll content, PSII maximum photochemical efficiency (Fv/Fm) and the electron transport rate (ETR) were significantly reduced. The activities of superoxide dismutase (SOD) and peroxidase (POD) and the photochemical quenching coefficient (qP) had no significant changes. The ultrastructure of the leaves was also observed. It was found that the stress caused the chloroplast properties change. The part of the grana thylakoid lamellae disappeared, and a large number of giant starch grains and osmiophilic globule appeared. After recovery for 2 days, the activities of SOD, POD, CAT, APX, soluble sugar, soluble protein and total chlorophyll contents decreased significantly, while the activities of GR and proline content increased significantly. The results indicated that the maximum temperature 57.7℃ for 3 days had significant effects on the antioxidant system and photosynthetic characteristics of sweet cherry leaves, and the chloroplast ultrastructure was significantly damaged, causing irreversible damage to the leaves. 参考文献 相似文献 引证文献