Stages Of Fruit Growth Research Articles

The metaxenia effects of different pollen grains on secondary metabolites enzymes and sugars of ‘Piarom’ date palm fruit

In this research, the characteristics of pollen were studied in eight pollinating cultivars of date palm, namely, ‘Shahani’, ‘Kabkab’, ‘Zahedi’, ‘Beraem’, ‘Faryab’, ‘Sheikhali’, ‘Fard’ and ‘Jarvis’. The characteristics were compared and metaxenia effects were evaluated on secondary metabolites, enzymes and other biochemical compounds of ‘Piarom’ date fruits. The evaluations were carried out during four stages of fruit growth and development. The pollen of these eight pollinating cultivars were compared in terms of carbohydrates, proteins, starch, total phenol, flavonoids, pectin methyl esterase, and amylase enzymes. According to the results, the pollen of ‘Sheikhali’, ‘Fard’, ‘Zahedi’ and ‘Shahani’ cultivars contained more of the above compounds, compared to the other cultivars. Regarding the effects of pollen on the composition of ‘Piarom’ date fruits, ‘Fard’ and ‘Sheikhali’ pollen produced the lowest amount of soluble tannin, which resulted in a better quality of ‘Piarom’ date fruits. Pollen was also obtained from ‘Sheikhali’ and ‘Fard’ cultivars for evaluations, showing that they led to the highest amounts of glucose and fructose in the fruits. Regarding the sucrose amount, ‘Jarvis’ and ‘Shikhali’ produced the best results. Pollen of ‘Sheikhali’ and ‘Fard’ cultivars caused the lowest amount of chlorophyll at the different stages of fruit growth, indicating a better decomposition of fruit chlorophyll and, as a result, better fruit quality. Pollen of ‘Sheikhali’ and ‘Fard’ cultivars produced the highest amounts of secondary metabolites such as total phenol, carotenoids and anthocyanin at the different stages of fruit development. The pollen of ‘Fard’ and ‘Sheikhali’ cultivars produced the highest levels of polygalacturonase, cellulase and invertase enzymes at different growth stages of the ‘Piarom’ date fruit. Regarding cellulase enzyme, fruits of the ‘Zahedi’ cultivar had more cellulase than the fruits of ‘Sheikhali’. In general, the pollen of ‘Fard’ and ‘Sheikhali, in comparison with other cultivars, improved the quantity and quality of ‘Piarom’ date fruits, due to their metaxenia properties.

Combination effects of preharvest tree net-shading and postharvest fruit treatments with salicylic acid or hot water on attributes of pomegranate fruit

Aril whitening (AW) or aril paleness is a physiological disorder in pomegranate fruit that occurs during fruit growth and developmental stages in main production areas in Iran, resulting to decrease in fruit quality. The aim of this study was to investigate the influence of preharvest green net shading and postharvest treatments of salicylic acid (SA) or hot water (HW) on fruit quality parameters and bioactive compounds of pomegranate cv. Ghojagh at harvest and during storage. This experiment was carried out on fruit of nine-year-old pomegranate trees growing under open field as control and trees covered under green 50% net shading for duration of about 4 months (June until the September, warmest months of the growth season). The fruits were harvested at the commercial stage and transferred to the laboratory, where subsequently treated by immersing in hot water (45 ºC) for 4 min or 2 mM SA at room temperature (2 min). As control postharvest treatment, a part of fruits were treated only with water for 4 min at room temperature. The fruits were then air-dried and transferred into a refrigerated storage at 4 ± 1 ºC, 80 ± 5% RH for a period of 90 days. A significant reduction in aril whitening, as well as fruit sunburn and cracking was observed from trees under 50%-green net shading in comparison with the control non-shading trees. Fruits of net shading had significantly higher bioactive compounds (ascorbic acid, phenolics and anthocyanin, antioxidant activity), less weight loss and lower chilling injury than the non-shading fruits during storage. Also, postharvest treatments, especially SA, had a good impact on reducing chilling injury and retaining the quality and nutritional value of pomegranate fruits.

Sensitivity to water deficit of the second stage of fruit growth in late mandarin trees

In citrus fruits, phases I and II of fruit growth are sensitive to water deficit, and for this reason, deficit irrigation (DI) has been usually restricted to the final ripening phase. However, the optimal timing and intensity of stress during sensitive phases have not been clearly defined. The main objective was to determine the sensitivity of the second stage of fruit growth to water deficit in adult mandarin trees, and to explore the suitability of different soil and plant water status indicators, including the leaf-scale spectrum, according to the water stress level. Four irrigation treatments were tested: a control (CTL) irrigated at ~ 80% of ETc during the entire crop cycle, and three irrigation suppression treatments, in which no water was applied during the end of phase I and the beginning of phase II (DI1), the second half of phase II (DI2), and phase III of fruit growth (DI3), respectively. Phase II of fruit growth can be considered as a non-critical phenological period until the fruit reaches approximately 60% of its final size, with the application of a water deficit using an irrigation threshold of midday stem water potential of − 1.8 MPa, and a cumulative water stress integral close to 28 MPa day. The novel visible infrared ratio index (VIRI) showed a high sensitivity for trees subjected to moderate and severe water stress and can be complementarily used to estimate on a larger temporal and spatial scale the plant water status. Wavelengths in the short-wave infrared (SWIR) region allowed differentiation between non-stressed, moderately, and severely water-stressed trees, and can be considered as an initial basis for determining the water status of mandarin trees at various stress intensities by remote sensing.

Genome-wide characterization and expression analysis of SAUR gene family in Melon (Cucumis melo L.).

We identified 66 melon SAUR genes by bioinformatic analyses. CmSAUR19, 38, 58, 62 genes are specifically expressed in different stages of fruit growth, suggesting their participation in regulating fruit development. Auxin plays a crucial role in plant growth by regulating the multiple auxin response genes. However, in melon (Cucumis melo L.), the functions of the auxin early response gene family SAUR (Small auxin up RNA) genes in fruit development are still poorly understood. Through genome-wide characterization of CmSAUR family in melon, we identified a total of 66 CmSAUR genes. The open reading frames of the CmSAUR genes ranged from 234 to 525bp, containing only one exon and lacking introns. Chromosomal position and phylogenetic tree analyses found that the two gene clusters in the melon chromosome are highly homologous in the Cucurbitaceae plants. Among the four conserved motifs in CmSAUR proteins, motif 1, motif 2, and motif 3 located in most of the family protein sequences, and motif 4 showed a close correlation with the two gene clusters. The CmSAUR28 and CmSAUR58 genes have auxin response elements located in the promoters, suggesting they may be involved in the auxin signaling pathway to regulate fruit development. Through transcriptomic profiling in the four developmental stages of fruit and different lateral organs, we selected 16 differentially-expressed SAUR genes for performing further expression analyses. qRT-PCR results showed that five SAUR genes are specifically expressed in flower organs and ovaries. CmSAUR19 and CmSAUR58 were significantly accumulated in the early developmental stage of the fruit. CmSAUR38 and CmAUR62 showed high expression in the climacteric and post-climacteric stages, suggesting their specific role in controlling fruit ripening. This work provides a foundation for further exploring the function of the SAUR gene in fruit development.

Genome-wide identification and expression profiling analysis of sucrose synthase (SUS) and sucrose phosphate synthase (SPS) genes family in Actinidia chinensis and A. eriantha

Sucrose synthase (SUS) is a common sugar-base transfer enzyme in plants, and sucrose phosphate synthase (SPS) is one of the major enzymes in higher plants that regulates sucrose synthesis. However, information of the SPS and SUS gene families in Actinidia, as well as their evolutionary and functional properties, is limited. According to the SPS and SUS proteins conserved domain of Arabidopsis thaliana, we found 6 SPS genes and 6 SUS genes from A. chinensis (cultivar: ‘Hongyang’), and 3 SPS genes and 6 SUS genes from A. eriantha (cultivar: ‘White’). The novel CDC50 conserved domains were discovered on AcSUS2, and all members of the gene family contain similar distinctive conserved domains. The majority of SUS and SPS proteins were hydrophilic, lipid-soluble enzymes that were expected to be found in the cytoplasm. The tertiary structure of SPS and SUS protein indicated that there were many tertiary structures in SPS, and there were windmill-type and spider-type tertiary structures in SUS. The phylogenetic tree was created using the neighbor-joining method, and members of the SPS and SUS gene families are grouped into three subgroups. Genes with comparable intron counts, conserved motifs, and phosphorylation sites were clustered together first. SPS and SUS were formed through replication among their own family members. AcSPS1, AcSPS2, AcSPS4, AcSPS5, AcSUS5, AcSUS6, AeSPS3, AeSUS3 and AeSUS4 were the important genes in regulating the synthesis and accumulation of sucrose for Actinidia during the fruit growth stages.

Metabolome and whole transcriptome analyses reveal the molecular mechanisms underlying terpenoids biosynthesis in Sapindus mukorossi fruits

Sapindus mukorossi fruit has been widely used as a source of daily necessities, cosmetics, biomedicine, and biodiesel due to its high terpenoids content. However, a systematic inventory of the regulatory mechanisms of terpenoids biosynthesis at different stages of fruit growth is still lacking. Here, we identified 50 terpenoid metabolites by terpenoid-targeted metabolomics and found that the most abundant kinds of terpenoids are triterpenoids and sesquiterpenoids. Mukurozioside and pyishiauoside of sesquiterpenoids were significantly upregulated in the mature fruit (S3) compared with the young fruit (S1) and mid-mature fruit (S2), indicating that they may be important factors leading to a high content of terpenoids. A total of 1669 differentially expressed (dif) lncRNAs, 13 dif-circRNAs, 219 dif-miRNAs, and 17,529 dif-mRNAs were identified by whole-transcriptome data. Enrichment analysis showed that these dif-RNAs were significantly enriched in phenylpropanoid biosynthesis, metabolic process, and plant hormone signal transduction. Co-expression and ceRNA network analysis showed that lncRNA:MSTRG.18127.1 was positively correlated with gma-miR156k, SmHSF14, and SmAXY4, regulating secondary metabolite biosynthesis. Correlation analysis between transcriptome and metabolite profiling showed that SmSE, Smβ-AS, SmCYP716A, SmUGT73, SmUGT94, SmTPS1, and SmTPS26 are key regulatory genes and that the upregulation of these genes may be beneficial to terpenoids biosynthesis. These findings can help elucidate the molecular mechanisms and regulatory networks of terpenoids biosynthesis in S. mukorossi and provide a biological basis for genomics-enabled improvements in molecular breeding.

Physico-chemical Changes in Assam Lemon (Citrus Limon Burm.) during Fruit Development and Maturation

Studies were conducted on the physico-chemical changes associated with fruit development in Assam lemon. Fruit growth was slow initially upto 95 days after fruit set (DAFS) and it increased rapidly in terms of fruit weight and size of the fruit, from 45.54g & 75.75 cm2 until maturity. The trend in specific gravity of the fruits increased with fruit development and reached the value to 2.7 at harvest maturity. Therefore specific gravity of the fruit could be considered as a reliable physical index for harvest maturity. During early stage of fruit growth the juice content percentage was found low which increased as fruit growth advanced towards maturity. Total soluble solids (TSS) to acidity ratio showed an increased trend during fruit development in Assam lemon. At maturity TSS to acidity ratio reached values between 1.99 to 2.810Brix. TSS to acidity ratio could also be considered as the reliable chemical index for harvest maturity. Bio chemical characteristics such as Ascorbic acid and Pectin content also showed an increasing trend with fruit development and maturity. However the chlorophyll content showed a down ward trend and at harvest maturity it recorded 0.185mg/g. Results indicated that Assam lemon attained full maturity at 135-140 days and harvest maturity in 130 days after fruit set.

Study The Effect of Antioxidants on The Traits of the Fruits of Two Cultivars of Jujube (Ziziphus mauritiana Lamk.) Al-Tufahi and Alarmouti Cultivars

This study was conducted in one of the private orchards in Al-Haritha region, Northern Basra city to study the effect of spraying antioxidants with three concentrations of (0, 3 and 6) ml.L-1 on two cultivars of jujube trees, Alarmouti and Altfahic. The physical traits of the stages of fruit growth were studied, starting from 50 days after flowering to the final maturity 120 days after of flowering. The results of the study recorded It is too complicated. The progress of the growth and development fruits for all the traits. The study revealed that the Alarmouti cultivar significantly excelled in most of the studied traits at all different growth stages, where the highest values ​​were recorded in the traits of size, length, diameter, and fruit weight (11.07 cm3, 35.99 mm, 27.40 mm, and 21.97 g) respectively. It also excelled in chemical traits during growth stages. The study also showed that the antioxidant concentration of 6 ml.L-1 significantly excelled in most of the studied physical and chemical traits. The bi-interaction also had a significant effect on the studied traits, while the fresh weight of the seed was not significant different between cultivars, concentrations, and their -interaction.

Usage and action mechanism of oxylipins including jasmonic acid on physiological aspects of fruit production

Plant hormones are associated with many physiological aspects in fruit tree growth and fruit production. Since jasmonates (jasmonic acid (JA) and methyl ester of JA (MeJA)), which are oxylipins from linolenic acid, were found in plants including fruits, many physiological and molecular actions of jasmonates to regulate fruit development and stress tolerance from the environment in fruit production have been studied. Jasmonoyl-L-isoleucine (JA-Ile) is a transporting and signaling substance for JA action in plants. In the JA signaling pathway, MYC transcription factors are key regulators, and the jasmonate-ZIM domain (JAZ) negatively affects MYC transcription factors in JA signaling.Jasmonates can promote anthocyanin production in fruit through the effects of MYB transcription factors. A chemically stable and practical compound in the field, the JA analog n-propyl dihydrojasmonate, has been developed to improve fruit coloration. Jasmonates interact with some other plant hormones. For example, the effects of jasmonates on ethylene metabolism and signaling differ with fruit growth stage. Jasmonate treatment before fruit maturation enhances ethylene production with ethylene biosynthesis and signaling genes. In contrast, jasmonate treatment after fruit maturation decreases ethylene biosynthesis. Jasmonates can mitigate abiotic and biotic stresses from the environment, such as drought, salt, temperature, and disease. When fruit or a fruit tree encounters environmental stress, the stress quickly increases levels of jasmonates, which acts as a kind of elicitor. In fact, treatment of fruit with jasmonates decreased the severity of chilling injury during storage and inhibited fungal infection.This review discusses the usage and action mechanisms of oxylipins including jasmonates on fruit coloration, crosstalk with other plant hormones, and environmental stresses in fruit production.

GCS-YOLOV4-Tiny: A lightweight group convolution network for multi-stage fruit detection.

Fruits require different planting techniques at different growth stages. Traditionally, the maturity stage of fruit is judged visually, which is time-consuming and labor-intensive. Fruits differ in size and color, and sometimes leaves or branches occult some of fruits, limiting automatic detection of growth stages in a real environment. Based on YOLOV4-Tiny, this study proposes a GCS-YOLOV4-Tiny model by (1) adding squeeze and excitation (SE) and the spatial pyramid pooling (SPP) modules to improve the accuracy of the model and (2) using the group convolution to reduce the size of the model and finally achieve faster detection speed. The proposed GCS-YOLOV4-Tiny model was executed on three public fruit datasets. Results have shown that GCS-YOLOV4-Tiny has favorable performance on mAP, Recall, F1-Score and Average IoU on Mango YOLO and Rpi-Tomato datasets. In addition, with the smallest model size of 20.70 MB, the mAP, Recall, F1-score, Precision and Average IoU of GCS-YOLOV4-Tiny achieve 93.42 ± 0.44, 91.00 ± 1.87, 90.80 ± 2.59, 90.80 ± 2.77 and 76.94 ± 1.35%, respectively, on F. margarita dataset. The detection results outperform the state-of-the-art YOLOV4-Tiny model with a 17.45% increase in mAP and a 13.80% increase in F1-score. The proposed model provides an effective and efficient performance to detect different growth stages of fruits and can be extended for different fruits and crops for object or disease detections.

Relação entre conteúdo de matéria seca, índices de maturação na colheita e qualidade de maçãs ‘Gala’ após armazenagem

Abstract The objective of this study was to determine the relationship among dry matter content (DMC) and maturity indexes at harvest and quality of ‘Gala’ apples after storage. Apple fruit of four ‘Gala’ strains produced on two rootstocks and three growing regions were used for experiments 1 and 2. For all experiments, fruit harvest maturity was assessed one day after harvest and stored fruit was assessed after removal from storage plus seven days at 22 °C. For experiment 1, fruit were harvested weekly along the final stages of growth and maturation on the tree. For experiment 2, fruit were harvested at commercial maturity and stored under a controlled atmosphere at 0.7 oC for 195 days. For experiment 3, fruit from two orchards were harvested at commercial maturity and stored in air at 1oC for 50, 110, or 194 days. DMC did not change during the final stages of fruit growth, however, there were significant changes in fruit firmness, starch index, and soluble solids content (SSC) during the same period. At the commercial harvest, fruit DMC showed high correlation with SSC, titratable acidity (TA) and firmness. DMC assessed at the commercial harvest also showed high correlation after storage with SSC and TA but not with firmness or flesh browning (FB). DMC decreased slightly during storage. The results show that DMC is not a reliable index to determine ‘Gala’ apple maturity at harvest, or to predict fruit firmness and FB after storage. However, DMC at harvest has potential to predict SSC and TA after storage, two important fruit quality traits. Fruit density at harvest showed utility to predict risk of flesh browning after storage.

A global meta-analysis of fruit tree yield and water use efficiency under deficit irrigation

Economical fruit trees are a kind of forest with great economic and ecological benefits, which has become an important cash source of many rural household incomes. However, the shortage of water resources has limited their development. Deficit irrigation (DI) is a novel water-saving irrigation method, but there is a risk of yield reduction in practice. Therefore, a meta-analysis was conducted to quantitatively analyze the impact of DI on fruit yield and water use efficiency (WUE) to explore the most suitable DI strategy for fruit trees. Overall, compared to full irrigation, DI decreased the fruit yield by 6.05% and increased WUE by 5.05%. However, the effectiveness of DI depended on DI factors, fruit tree varieties and environmental factors. In order to achieve a win-win goal of water-saving and yield increasing, a Win-Win analysis was conducted on collected data. It was found that DI was suitable for drought-tolerant tree varieties in the arid region with medium-textured and large bulk density soil. Adopting subsurface irrigation methods for low or moderate deficit (Irrigation limit ＞55%θf) before the fruit growth stage (i.e., bud burst to leafing stage and flowering to fruit set stage) was recommended. Our findings can provide implications for applying DI to fruit trees.

Physiological Activity, Nutritional Composition, and Gene Expression in Apple (Malus domestica Borkh) Influenced by Different ETc Levels of Irrigation at Distinct Development Stages

Managing irrigation efficiently is paramount given the uncertainty in the future availability of water and rising demand for this resource. Scheduled irrigation significantly influences vegetative growth through improving crop physiology and nutrient uptake and use efficiency. Influence of different irrigation treatments (100%, 75%, and 50% volume of Class A pan evapotranspiration) applied at four different phenological stages (flowering and fruit set (C1), fruit growth stage (C2), pre-harvest stage (C3), and throughout the growing season (C4)) through drip along with a control (rainfed) on leaf physiology, nutrient content, and uptake through gene expression was studied on Super Chief Sandidge variety raised on M9T337 (5 and 6 years old) grown at a spacing of 1.5 × 3 m (2222 plants/ha) under high density condition of Kashmir Himalayan range of India. A comparison of data reveals that drip irrigation at 100% Crop evapotranspiration (ETc) increased leaf area by 60% compared to rainfed conditions. Leaf area significantly increased in plants irrigated throughout the growing season (C4) and during flowering and fruit set stage (C1). Irrigation amount likely does not have any influence on leaf development after the fruit growth stage. Stomatal opening and their size greatly vary from no irrigation to optimum irrigation in these plants. High density apple trees exposed to optimum irrigation levels (100% and 75% ET) had significantly higher concentrations of nutrients (N, P, and K) in their leaf tissues. The concentration of Ca and Mg content in leaf tissues are greatly influenced by the optimum supply of water during the early growth stages of apple growth. The availability of water significantly influences nutrient transporter gene expression and thus nutrient uptake by regulating such transporter genes. It is therefore observed that proper irrigation during C1 and stage C2 stage are the critical growth stages of apple for optimum leaf physiological activity and proper nutrient uptake.

Effects of Pollination Interventions, Plant Age and Source on Hormonal Patterns and Fruit Set of Date Palm (Phoenix dactylifera L.)

Date palm is widely propagated through conventional offshoots. It is also produced through a tissue culture technique due to the limited number of offshoots produced throughout the course of a palm’s life. Being dioecious, it is a cross-pollinated tree that can be naturally or artificially pollinated. Tissue-cultured plants often have abnormal epigenetic or genetic changes that affect specific phenotypic characteristics. The growth of parthenocarpic fruits in date palms is mostly induced by hormonal imbalances in certain tissues. The major hormones in parthenocarpic fruits are auxins (IAA), gibberellins (GA3), and abscisic acid (ABA). Parthenocarpic, or abnormal fruit development, is an undesirable trait for date palm growers since it drastically reduces farm income. The current study was therefore conducted over two seasons to confirm previous observations and included conventional offshoot-derived trees (CO) and tissue culture-derived ones (TC) of the cultivar Barhee. According to the observed ratio of the fruiting abnormalities, two date palm tree ages were selected, i.e., 6 and 13 years. Two pollination interventions were used: pollination of naturally open female spathes (NOP) and pollination of forced open female spathes (FOP). Plant hormones, IAA, GA3, and ABA were identified just before pollination and at specific intervals after pollination for up to 85 days. The ratio of the abnormal fruit set was identified 5 days after pollination. Significant differences were observed in hormonal levels between tree ages as well as between tree propagation sources. Young TC trees (6-year-old) had high abnormal fruit sets compared to CO date palm trees that were the same age. During the early fruit growth and development phases, CO date palms had much higher amounts of IAA and GA3 than TC date palms. However, ABA concentrations were surprisingly higher in the TC trees during the early fruit growth stages, while it immediately decreased after pollination in the CO date palms. The ratio of abnormal fruits was significantly reduced in the 13-year-old TC date palms, and no differences were observed compared to the CO ones. The levels of IAA, GA3, and ABA hormones in both young and old date palms derived through CO or TC followed similar patterns. The critical observations regarding the ABA pattern in the old TC date palms (13-year-old) gradually dropped after pollination, which was identical to the CO ones, whereas it was the opposite in the young 6-year-old TC date palm plants.

Continuous Monitoring of Olive Fruit Growth by Automatic Extensimeter in Response to Vapor Pressure Deficit from Pit Hardening to Harvest

Recently, several studies on olive fruit growth have focused on circadian monitoring as an important orchard management tool. The olive fruit growth trend is described by double sigmoid model with four growth phases, where the third phase spans from the end of pit hardening to initial fruit maturation, and the last phase includes olive maturation up to fruit drop. Environmental factors play an important role in fruit growth, with vapor pressure deficit (VPD) being a keystone factor. Our experiment was designed to hourly monitor olive (Olea europaea L. cv. ‘Frantoio’) fruit transversal diameter from approximately initial pit hardening (II Phase), extension (III Phase) until harvest time (IV Phase) in the attempt to determine whether fruit growth dynamically responds to environmental variables such as diurnal VPD change in different stages of fruit development. Automatic extensimeters were applied in open field and VPD was calculated from data of our weather station. Throughout the experiment period, the circadian model of fruit growth showed two steps: shrinkage and expansion. Almost in all days of the third phase of fruit growth, daily response of transversal diameter to VPD formed complete clockwise hysteresis loops. During the fourth phase of fruit growth, with increasing fruit maturation, the complete clockwise hysteresis loop experienced some abnormality. At the fourth stage of fruit growth there were incomplete and partial clockwise hysteresis loops. We conclude that hysteresis can be employed to detect the shift between the end of the third phase (cell expansion) and the beginning of the fourth phase (fruit maturation) of fruit growth. The disappearance of the complete clockwise hysteresis loop and the substitution with incomplete, or partial clockwise hysteresis loops was observable only in the fourth stage of fruit growth. These results can be valuable for any smart fruit management of olive fruit production.

Early apple fruit development under photoselective nets

The objective of this 2-year study (2017, 2019) was to evaluate the influence of photoselective nets on apple fruit growth, focusing on the initial fruit growth stages of “Pink Lady”. Trees were subjected to four photoselective nets (Blue, Red, White and Yellow) and a standard black one (serving as Control), resulting in 5 light environments (LE), all shading at 20%. From 20 to 90 DAFB, 32 fruit and extension shoots, for each LE, were measured for a total of 11 times during the season. For each LE, fruit gauges were also installed to monitor fruit daily growth parameters, from 50 to 90 DAFB. At harvest, all fruit from each light environment were weighed and quality parameters were measured on 40 fruit per treatment. For each year, correlations were made to test the influence of LEs on final fruit weight and quality, and the impact that extension shoot growth had on fruit growth. In both years, white and control nets led to the production of fruits with higher weight compared to the other treatments (blue, red and yellow nets). In 2019, LEs did not appear to influence the relationship between shoot and fruit growth, probably due to the higher crop load and the massive pruning carried out the previous year. The higher vegetative outburst in this year might have unbalanced resources towards the shoots, than towards the fruit. Results show how weather and orchard management heavily influenced the trees responses. Yet, the consistent findings of final fruit weight, for both years, indicate that different wavelengths influence fruit and shoot behavior, even at early phenological stages. Hence, growers searching for bigger fruit should refer to white and black nets. Further studies approaching this technology can help improve apple production management and knowledge of the use of photoselective nets.

Foliar Application of Salicylic Acid at Different Phenological Stages of Peach Fruit CV. 'Flordaking' Improves Harvest Quality and Reduces Chilling Injury during Low Temperature Storage.

Peaches are well-liked amongst the stone fruits in Pakistan. The peach industry faces significant losses, from harvesting to marketing. The objective of this study was to investigate the effectiveness of foliar sprays of salicylic acid (SA) on the fruit quality of peaches (cv. ‘Flordaking’) at the harvest and postharvest life or stages. Different concentrations of SA (control, 1, 2 and 3 mM) were sprayed on the plants at three growth stages of fruit, i.e., the cell division, cell enlargement and pit-hardening stages. In general, all the SA treatments improved the fruit quality at harvest and maintained higher levels of flesh firmness, titratable acidity and ascorbic acid during storage. However, fruit weight loss, soluble solid contents, membrane leakage, chilling injury, color development, disease and decay incidence and the climacteric peak of ethylene were lowered by SA treatment after six weeks of low-temperature storage. SA at a 3-mM concentration was proven to be the most effective in maintaining the quality for a longer period of time during low-temperature storage. Based on the results, it can be concluded that the application of SA at fruit development stages can improve the harvest quality and storability of ‘Flordaking’ peaches.

Effects of water deficit and salinity stress on late mandarin trees

To maintain the viability of citrus farms in a scenario of scarce water supplies for irrigation purposes, such as in south-eastern Spain, it is necessary to detect the maximum threshold of crop water status and vegetative growth, both of which are vulnerable to the combined effect of water and salinity stress. With this aim, adult late mandarin trees were subjected to a gradual increase in salinity of the irrigation water for four consecutive growing seasons, accompanied by a water deficit for the first three seasons, while the fourth season counted as a recovery period. The treatments tested were: i) control (CTL), irrigated at 100% of the ETc in the first season followed by an additional 33% water leaching requirement in the second and third seasons; (ii) a regulated deficit irrigation (RDI100) treatment, irrigated as the CTL except in phase I and until mid-phase II, coinciding with the beginning of the slowdown in trunk growth, where irrigation was set at 65 and 50% CTL in the first and last two seasons, respectively, and 80% in phase III; (iii) RDI50, irrigated as the CTL during the first season, and from the second season onwards, at 50% RDI100 during the deficit period; (iv) FARMER, irrigated in accordance with the farmer's criteria. A moderate saline water stress combined with the application of RDI100 treatment did not reduce crop yield after one growing season, but did reduce plant growth. However, after two consecutive seasons (in both RDI strategies) water stress drastically reduced both yield and plant growth, mainly due to a high accumulation of sodium and chloride in the leaves. Gas exchange parameters were also greatly reduced. Furthermore, it was found that the water deficit could be prolonged until the trunk growth slowed down during the second fruit growth stage in mandarin trees, leading to a substantial increase in water productivity values.

Disentangling the link between leaf photosynthesis and turgor in fruit growth.

Despite the importance of understanding plant growth, the mechanisms underlying how plant and fruit growth declines during drought remain poorly understood. Specifically, it remains unresolved whether carbon or water factors are responsible for limiting growth as drought progresses. We examine questions regarding the relative importance of water and carbon to fruit growth depending on the water deficit level and the fruit growth stage by measuring fruit diameter, leaf photosynthesis, and a proxy of cell turgor in olive (Olea europaea). Flow cytometry was also applied to determine the fruit cell division stage. We found that photosynthesis and turgor were related to fruit growth; specifically, the relative importance of photosynthesis was higher during periods of more intense cell division, while turgor had higher relative importance in periods where cell division comes close to ceasing and fruit growth is dependent mainly on cell expansion. This pattern was found regardless of the water deficit level, although turgor and growth ceased at more similar values of leaf water potential than photosynthesis. Cell division occurred even when fruit growth seemed to stop under water deficit conditions, which likely helped fruits to grow disproportionately when trees were hydrated again, compensating for periods with low turgor. As a result, the final fruit size was not severely penalized. We conclude that carbon and water processes are able to explain fruit growth, with importance placed on the combination of cell division and expansion. However, the major limitation to growth is turgor, which adds evidence to the sink limitation hypothesis.

Pollen grain hormones of date palm pollinator cultivars and their relationship with hormones of different stages of ‘Piarom’ date fruit growth

The aim of this study was to investigate the metaxenia effect of pollen grain hormones of date palm pollinators on the hormones of different stages of fruit growth. The relationships between auxin, cytokinin, gibberellin and abscisic acid hormones of ‘Shahani’, ‘Kabkab’, ‘Zahedi’, ‘Beraem’, ‘Faryab’, ‘Sheikhali’, ‘Fard’ and ‘Jarvis’ pollen grains with the amount of the same hormones in different stages of ‘Piarom’ fruit development were studied. The results showed that pollen grains of different date palm pollinators have different amounts of these hormones. Pollen grains of ‘Fard’ and ‘Sheikhali’ cultivars have higher amounts of hormones compared to other cultivars. The amount of these hormones was also very variable at different stages of fruit growth. The highest amount of hormones in different stages of ‘Piarom’ date fruit growth was observed in trees that were pollinated with pollen grains of ‘Fard’ and ‘Sheikhali’ cultivars. Also the amount of these hormones in pollen grains and different stages of fruit growth had a positive linear relationship. The positive correlation between pollen grains hormones and hormones of different stages of fruit growth confirms the metaxenia effect of pollen grains on the characteristics of ‘Piarom’ date fruit. The presence of more hormones in the fruit, which is directly related to the amount of these hormones in pollen grains, improves the quantity and quality of date palm fruits.