Physiological Fruit Research Articles

Sustainable Crop Production Systems and Human Nutrition

There is a pressing need for redesigning agriculture to achieve sustainability and for utilizing modern genetic tools, including genetic engineering, to add nutritional value to crops for the benefit of the diverse human population. Collectively, plant foods contain most minerals, macronutrients (calories), and micronutrients essential for human nutrition. These plant foods also contain a range of bioactive compounds that can play important roles in the prevention of chronic diseases including heart disease, cancer, stroke, diabetes, Alzheimer’s, cataracts, and age-related functional decline. However, these bioactive nutrients are often present at marginal concentrations in edible plant tissues in regard to human nutrition/prevention of disease. The quantity of these nutrients in edible plant tissues is primarily dependent on crop genetics and regulated by complex and overlapping mechanisms in response to developmental and environmental cues. Environmental cues are naturally occurring - temperature, light intensity and other stressors, or result from crop production system components - fertilizer, tillage operations, etc. One strategy for sustainable, next-generation crop development is to design cropping systems that have minimal or lesser impact on the environment and to use genetic approaches to enhance crop nutritional content. This strategy is appealing since crop genetics is the primary driver of plant nutrient content and because purely managing crop production fields to optimize crop nutrient content is extremely challenging if not impossible. As an example we present the development of a next-generation sustainable tomato production system with beneficial impacts on tomato physiology and nutritional quality of the tomato fruit. Our analysis of the metabolomes of tomato cultivars in this and other cropping systems highlights the need for robust cultivars that consistently express nutritional and other desirable traits across cropping systems and under differing environmental conditions.

Nitric oxide in the physiology and quality of fleshy fruits.

Fruits are unique to flowering plants and confer a selective advantage as they facilitate seed maturation and dispersal. In fleshy fruits, development and ripening are associated with numerous structural, biochemical, and physiological changes, including modifications in the general appearance, texture, flavor, and aroma, which ultimately convert the immature fruit into a considerably more attractive and palatable structure for seed dispersal by animals. Treatment with exogenous nitric oxide (NO) delays fruit ripening, prevents chilling damage, promotes disease resistance, and enhances the nutritional value. The ripening process is influenced by NO, which operates antagonistically to ethylene, but it also interacts with other regulatory molecules such as abscisic acid, auxin, jasmonic acid, salicylic acid, melatonin, and hydrogen sulfide. NO content progressively declines during fruit ripening, with concomitant increases in protein nitration and nitrosation, two post-translational modifications that are promoted by reactive nitrogen species. Dissecting the intimate interactions of NO with other ripening-associated factors, including reactive oxygen species, antioxidants, and the aforementioned phytohormones, remains a challenging subject of research. In this context, integrative 'omics' and gene-editing approaches may provide additional knowledge of the impact of NO in the regulatory processes involved in controlling physiology and quality traits in both climacteric and non-climacteric fruits.

Preharvest UV-C treatment affected postharvest senescence and phytochemicals alternation of strawberry fruit with the possible involvement of abscisic acid regulation

As an environmentally friendly approach for fruit quality improvement, the effect of preharvest UV-C on the physiology of strawberry fruit during postharvest storage remains to be assessed. Strawberry fruit developed with supplementary UV-C were stored at room temperature for 2 weeks. Preharvest UV-C attenuated fruit postharvest senescence and altered phytochemicals composition. Higher ester titer was found in the treated fruit at harvest, whereas higher terpene and furanone contents were detected after 72 h of storage. At harvest, polyphenolics accumulated to a higher level in UV-C group, but the difference disappeared after 24 h of storage. Meanwhile, the intrinsic level of abscisic acid and the expressions of FaPYR1, SnRK2, and FaASR in the UV-C-treated fruit was enhanced at harvest but returned to a lower level as storage proceeded. This study highlights the time-dependent effect of preharvest UV-C on strawberry fruit postharvest biochemical indexes and the possible involvement of abscisic acid signaling factors.

Effects of regulated deficit irrigation on soil salinity, physiological processes and fruit quality of gray jujube under desert conditions.

Regulated deficit irrigation (RDI) was applied to gray jujube trees in an oasis region, to determine the effects of this irrigation system on soil salinity, gray jujube physiological processes, fruit yield, and fruit quality. Treatments consisted of severe, moderate and low deficit irrigation (irrigated with 85%, 70% and 55% of CK, respectively) at the flowering stage to fruit set stage. During the other growth stages, all treatments were irrigated with 80% of pan evaporation, which was the same as that in control. The results indicated that soil salinity was enhanced during the periods of water stress, but the high value of soil salinity declined by 3.48%-37.27%, at each depth, after irrigation was resumed. RDI caused a decline in the photosynthetic rate, transpiration rate, and stomatal conductance, but enhanced the water use efficiency of the leaves. However, the leaf photosynthetic rate was effectively enhanced after the recovery of irrigation, especially in the moderate deficit irrigation treatment, which exceeded the control. This led to an improved fruit yield, which was 9.57% higher than that of the control. The deficit treatments caused a significant increase in the soluble solid content, soluble sugar content, single fruit weight and sugar/acid ratio. Enhanced vitamin C content, resulting from deficit treatments, has also been observed in the gray jujube. Therefore, this research shows that RDI provides some benefits in the production of gray jujube trees in desert conditions. Keywords: regulated deficit irrigation, soil salinity, gray jujube, water use efficiency, photosynthetic rate, transpiration rate, stomatal conductance, soluble solid content, sugar/acid ratio DOI: 10.25165/j.ijabe.20191203.4262 Citation: Liu Z P, Zhu C L, Wu S Y, Guo W H, Abudushalamu Y, Jiao X Y, et al. Effects of regulated deficit irrigation on soil salinity, physiological processes and fruit quality of gray jujube under desert conditions. Int J Agric & Biol Eng, 2019; 12(3): 52–59.

제주도에서 생육시기별 기후변동이 감귤 생산량에 미치는 영향

This study aims to investigate the effects of climatic variability on the citrus yield in Jeju-do. This study analyzed the relationship between the citrus yield and climate elements(temperature, rainfall, sunshine duration etc) at each growing season. Temperature shows a positive relationship with the period of flower bud for the yield of citrus. The rainy days of bud bursting period have a negative relation in Seogwipo area. The sunshine duration of the 1st physiological fruit drop period was positively related to citrus yield in Jeju and Seogwipo area. The maximum temperature of the 2nd physiological fruit drop period and the fruit enlargement period were negatively related to the citrus yield. In Jeju and Seogwipo area, about 60% of the variation of citrus yield is explained by the variation of climatic factors. The sunshine duration of the 1st physiological fruit drop period and fruit enlargement period were selected to the yield estimation in Jeju. In Seogwipo, the number of rainy days and the sunshine duration of the 1st physiological fruit drop period were selected.

Activation of the phenylpropanoid biosynthesis pathway reveals a novel action mechanism of the elicitor effect of chitosan on avocado fruit epicarp

Secondary metabolites play an important role in the avocado fruit defense system. Phenolic compounds are the main biosynthesized metabolites of this system response. Our objective in this investigation was to evaluate the induction of specific metabolic pathways using chitosan as an elicitor. Extracts obtained from avocado in intermediate and consumption maturity stages treated with chitosan exhibited an increase in antifungal activity, which caused inhibition of mycelial growth and a decrease in sporulation as well as spore germination of Colletotrichum gloeosporioides. Additionally, RNA from epicarp of the fruits treated and untreated with chitosan was obtained in order to evaluate the expression of genes related to phenylpropanoids and the antifungal compound 1-acetoxy-2-hydroxy-4-oxo-heneicosa-12,15-diene biosynthesis. An increased in gene expression of genes that participates in the phenylpropanoids route was observed during the stage of physiological fruit maturity, others genes such as Flavonol synthase (Fls), increased only in samples obtained from fruit treated with chitosan at consumption maturity. Our results reveal a new molecular mechanism where chitosan induces a specific accumulation of phenylpropanoids and antifungal diene; this partially explains avocado's resistance against fungal pathogens. Finally, we discuss the molecular connections between chitosan induction and gene expression to explain the biological events that orchestrate the resistance pathways in fruits.

Rhamnogalacturonan lyase: a pectin modification enzyme of higher plants

Plant cell wall is constituted by three main polysaccharides: cellulose, hemicellulose and pectin. The principal pectin domains comprise homogalacturonan, rhamnogalacturonan I (RG-I) and ramnogalacturonan II. Rhamnogalacturonan lyase (RGL) enzyme is capable of catalyzing the degradation of the RG-I backbone by a b-elimination mechanism. RGL enzyme have been studied in fungi and bacteria species, however, little data is available related with its function in plant biology. This review tries to fill the gaps on the knowledge about RGL enzyme. Here, we discuss our recent published work regarding the role of RGL in plants. In addition, we highlight results from different sequence analysis, RGL activity and function associated with plant development and fruit ripening, as well as its role in cell wall structure. The knowledge of this enzyme is essential to comprehend and elucidate its role in plant and fruit physiology.

Evaluation of the adaptability, productivity, and leaf powder quality of eight Moringa oleifera cultivars introduced to a dry-hot climate of Southwest China

Although Moringa oleifera is a globally recognized multipurpose plant, and its seed-oil has been identified as an industrial source for the manufacture of cosmetic emollient, there is however lack of conclusive data on its performance in China, which is the most northerly latitude of moringa distribution in the world today. The objectives of this study were to (i) determine the adaptability, and (ii) evaluate the yield potential of seed-oil and quality characteristics of leaf powder from eight M. oleifera cultivars (‘Mali’ [ML], ‘Kenya’ [KE], ‘USA’ [US], ‘Cuba’ [CU], ‘Bangalore’ [BL], ‘Calcutta’ [CT], ‘Taiwan’ [TW], and ‘Myanmar’ [PO]) in the dry-hot regions of southwest China from 2014 to 2015. Evaluated cultivars showed variations in the studied vegetative and reproductive growth traits i.e. tree height, canopy diameter, and the number of branches producing fruit (NBF), etc. The results showed that the PO cultivar had the highest total number of ripe fruit loads (NRF). Although the plants from the US cultivar had the maximum number of fruit settings (NTF), they produced the smallest NRF/NTF ratio, suggesting that plants from different geographical provenances differed in their adapting to varied environments and a severe physiological fruit drop in the US cultivar. Also, the evaluated cultivars showed differences in the studied fruiting traits and yield components i.e. the number of seeds per fruit pod (NSF), seed weight, seed yield, and seed oil content. Among the plants assessed, M. oleifera from the PO produced significantly higher (P < 0.05) seed and oil yields per hectare, with respective average values of 1025 kg·ha−1 and 321 kg·ha−1 throughout the two evaluation years. In addition, nutrient variability in leaf powder as a fodder resource was analyzed for crude lipid, crude protein, and fibre components contents. There were no significant differences (P < 0.05) between the eight cultivars in the crude fiber, crude lipid, ash or dry matter (DM) contents, but the CT and BL cultivars exhibited significantly (P < 0.05) higher crude protein levels and in vitro dry matter digestibility (IVDMD) concentrations. These findings suggested that the best varieties regarding seed oil yield and leaf powder quality may be the PO cultivar from Myanmar, and CT and BL cultivars from India, respectively.

Optimizing shelf life conditions for anthocyanin-rich tomatoes.

Shelf life is the time a product can be stored without losing its qualitative characteristics. It represents one of the most critical quality traits for food products, particularly for fleshy fruits, including tomatoes. Tomatoes’ shelf life is usually shortened due to fast over-ripening caused by several different factors, among which changes in temperature, respiration and pathogen exposure. Although tomatoes usually do not contain anthocyanins, varieties enriched in these antioxidant compounds have been recently developed. The anthocyanin-rich tomatoes have been shown to possess a significantly extended shelf life by delayed over-ripening and reduction of the susceptibility to certain pathogens. In the present work, we compared different conditions of postharvest storage of anthocyanin-rich tomato fruits with the aim to understand if the added value represented by the presence of the anthocyanins in the fruit peel can be affected in postharvest. For this purpose we used an anthocyanin-enriched tomato line derived from conventional breeding and took into consideration different light and temperature conditions, known to affect fruit physiology during postharvest as well as anthocyanin production. Several quality traits related to the fruit ripening were measured, including anthocyanin and carotenoid content, pH, titratable acidity and total soluble solids. In this way we identified that the most suitable fruit storage and postharvest anthocyanin accumulation were obtained through exposure to cool temperature (12° C), particularly in the presence of light. Under these parameters, tomato fruits showed increased anthocyanin content and unchanged flavour-related features up to three weeks after harvesting.

Differences in flower and fruit drop patterns in almond cultivars

Self-fertility in almond is one of the main aims in the Spanish breeding programs. However, productivity depends not only on the level of self-fertility but also in other factors such as the number of flowers produced, on the percentage of fruit set and on the fruit weight. These yield components are genotype-dependent and are influenced by climatic and management conditions. The almond tree like other fruit trees shows a regulation effect of the productive load that can occur with flower drops and can continue with fruit drops, to be able to reach a good balance between crop load and vegetative growth. In this work, the pattern of the physiological flower and fruit drops in different almond cultivars was evaluated. The work was carried out in a plot in Lleida (Northeastern Spain) set in a randomized blocks trial (4 replicates of each cultivar and 4 trees replicate-1). The number and the evolution of flowers and fruits were assessed every 15 days, from pink bud to nut harvest. The evaluation was carried out in two shoots per replication and using four blocks for each cultivar. The results of one year study (2016) showed two different flower and fruit drop patterns which are modulated according to cultivar and their phenological evolution. The cultivar patterns differ considering the productive organ that drops, the time when the drops occur and the severity of the drops.

Micro-structural and quality changes in growing dark-purple eggplant (solanum melongena L.) as affected by the harvest season

Whereas the production season is accepted to exert profound influence on fruit physiology, micro-structure and quality, very few studies have attempted to find liaisons between these traits. Herein, we determined the micro-structural and quality changes of eggplant fruit produced in Late Spring (mean air temperature 22 °C; max. 28 °C; min. 16 °C), Late Summer (mean air temperature 19 °C; max. 25 °C; min. 13 °C) and Late Fall (mean air temperature 11 °C; max. 15 °C; min. 6 °C), at three growing stages: Baby (S1, 9 cm length), Commercially mature (S2, 17 cm length) and Advanced commercially mature (S3, 21 cm length). We followed fruit elongation and assessed at harvest the size of epidermal and parenchyma cells, cuticle thickness, respiration rate, dry matter, firmness, seed number, seed size and seediness. The time required to reach commercial maturity was 3–4 times shorter in Late Spring than in Late Fall. Micro-structural evaluations showed that Late Spring fruit had epidermal and epicarp cells per unit area than Late Fall eggplants, which in turn presented thinner cuticles and a less compact large-celled central endocarp parenchyma. Commercially mature Late Fall eggplants also lighter color, showed lower respiration and were firmer than fruit growing earlier in the season. For all maturity stages fruit dry matter content was the parameter correlating best with fruit firmness (r = 0.71). Late Summer fruit tended to show intermediate properties, but had higher seed number, size and seediness. Overall, results show the influence that the growing season exerts on eggplant metabolism, micro-structure and quality.

Hydrogen Sulfide: A Potent Tool in Postharvest Fruit Biology and Possible Mechanism of Action.

Hydrogen sulfide (H2S), an endogenous gaseous molecule, is considered as a signaling agent, in parallel with other low molecular weight reactive substances, mainly hydrogen peroxide (H2O2) and nitric oxide (NO), in various plant systems. New studies are now revealing that the postharvest application of H2S, through H2S donors such as sodium hydrosulfide (NaSH) or sodium sulfide (Na2S), can inhibit fruit ripening and senescence programs in numerous fruits. We discuss here current knowledge on the impact of H2S in postharvest physiology of several climacteric and non-climacteric fruits such as banana, apple, pear, kiwifruit, strawberry, mulberry fruit, and grape. Although there is still a considerable lack of studies establishing the mechanisms by which H2S signaling is linked to fruit metabolism, we highlight several candidate mechanisms, including a putative cross-talk between H2S and ethylene, reactive oxygen and nitrogen species, oxidative/nitrosative stress signaling, sulfate metabolism, and post-translational modification of protein cysteine residues (S-sulfhydration) as being functional in this H2S postharvest action. Understanding H2S metabolism and signaling during postharvest storage and the interplay with other key player molecules would therefore provide new, improved strategies for better fruit postharvest storage. To achieve this understanding, postharvest fruit physiology research will need to focus increasingly on the spatial interaction between H2S and ethylene perception as well as on the interplay between S-sulfhydration/desulfhydration and S-nitrosylation/denitrosylation under several postharvest conditions.

Effects of 2,4-DP- P (2,4-Dichlorophenoxypropionic Acid-P) Plant Growth Regulator on Fruit Size and Yield of Star Ruby Grapefruit (Citrus paradisi Osb.)

Star Ruby is the main grapefruit (Citrus paradisi) variety grown in Turkey; however, small fruit size is a common problem in ‘Star Ruby‘ grapefruit. Fruit size is a decisive external quality parameter in citrus at the marketing of fresh citrus fruits. Fruit size can be enhanced by several techniques such as girdling and thinning. Various plant growth regulators are known to affect the growth and size of citrus fruit. The objective of the present study was to observe the effects of 2,4 dichlorophenoxypropionic acid-p (2,4-DP-P) on the fruit size, yield and quality of Star Ruby from 20-year-old trees budded on sour orange rootstock in Adana, Turkey in 2007. Four concentrations (50, 100, 150 and 300 ppm) of 2,4-DP-P were applied 8 weeks after anthesis during physiological fruit drop when the mean fruit diameter was 13-15 mm. The results indicated that the application of 2,4-DP-P increased the fruit size of Star Ruby grapefruit without reducing yield. The application had a significant effect on fruit yield except for trees treated with 50 ppm 2,4-DP-P. Compared with the control trees, applications of 2,4-DP-P increased the number of large, commercially valuable Star Ruby (&gt;93 mm, 89-93 mm and 84-89 mm). No effects were determined on fruit internal quality parameters. Thus, the results of the present study revealed that 2,4-DP-P can be used to improve the fruit size of Star Ruby fruitlets during the June drop.

Effect of time of harvest and packaging on quality and shelf life of litchi fruit

Generally in India, postharvest operations such as sorting, grading and packaging of harvested litchi fruit are done at the orchard itself due to non-availability of pack-house at farm and nearby places. Considering the available facilities vis-a-vis prevailing harsh weather conditions during harvesting period and rapid changes in physiology of litchi fruits, a study was carried out during 2013-2014 and 2014-2015 with the objective to assess the effect of harvesting time and improved packaging technique on shelf life of litchi fruit. Mature fruits were harvested early in the morning starting from 4 to 12 am and grouped in three lots (up to 6, 9 and 12 am). Fruit quality parameters, viz., fruit weight, pericarp properties, anthocyanin content, respiration rate, TSS and acidity were analyzed. The fruits were packed in 2-kg ventilated CFB boxes using two types of perforated polymer lining material and kept at ambient condition (32±2°C and 49±2% RH) for one week. It was evident that the fruit lot harvested late in sunny day (10 am onwards) and packed traditionally (without polymer lining) showed rapid loss of pericarp moisture accompanied by visually perceivable pericarp browning within three days under ambient storage condition. Fruit harvested early in the morning (6 AM), kept in perforated mono-polymer bag and packed in 2-kg CFB boxes recorded least physiological loss in weight (6.8%), browning index, respiration rate (116.2 mL CO2 kg(-1) h(-1)) and maximum anthocyanin content 28.36 mg 100 g-1 peel) as well as marketable fruits (74%) after 5 days of storage at ambient condition. Fruit harvested in sunny hours (10 am onwards) and kept in perforated polymer bags and packed in CFB box resulted in 62% marketable fruits, after 5 days of storage. Thus based on the studies, it can be advised to harvest litchi fruits early in the morning and pack them in CFB boxes with perforated mono-polymer lining.

The fruit microbiome: A new frontier for postharvest biocontrol and postharvest biology

Microorganisms are an integral part of the composition of fruits and vegetables and are found as epiphytes on the surface or as endophytes within tissues. The realization that fruit surfaces harbor beneficial microorganisms fostered the field of biological control using epiphytic microorganisms which led to the development of several commercial biocontrol products. Advances in DNA sequencing and “omics” technologies have enhanced our ability to characterize the diversity and function of microbial communities (microbiome) present in and on plant tissues. Microbiome studies have the potential of providing knowledge that will lead to a fundamental paradigm shift in the way we think about biocontrol strategies, biocontrol products, and postharvest biology, as well as the health attributes of fruits and vegetables. Fruit microbiome research will enhance our understanding of harvested commodities as an ecosystem in which the microbiome plays an essential role in the health and physiology of fruit after it is harvested. Meta-omic (metagenomics, metatranscriptomics, metaproteomics, and metametabolomics) technologies are only beginning to be applied to postharvest studies and will revolutionize our understanding of postharvest biocontrol systems, foodborne pathogens, and postharvest physiology. The role of the microbiome in plant health, productivity, and cultivar development should be considered as much as the plant itself. Plant breeding or genetic modification of plants could be used to intentionally modulate the composition of the microbiome and its function, recruiting disease antagonists and plant-growth promoters that enhance plant health and the quality of the harvested products. Increased knowledge of microbial community systems will lead to the development of natural or synthetic consortia that can be used to prevent postharvest diseases and mitigate physiological disorders in harvested commodities.

Insect pollination as a key factor for strawberry physiology and marketable fruit quality

About 35% of global crop production arises from crop species that benefit from animal pollination, especially by insects. Animal pollination can enhance yields and increase fruit quality, but the effects of insect pollination on pre- and post-harvest fruit physiology and quality are largely unknown. For the first time, we analysed in much detail the physiological responses of fruit development and marketable quality improvements to different pollination treatments such as self-pollination, open-pollination and hand-pollination. In strawberries, self-pollination led to reduced seed set (fertilized achenes), reduced concentration of the phytohormone auxin, highest share of deformed fruits (>90%), smallest and lightest fruits, considerably lower commercial value (8% of the value of open- or hand-pollinated fruits), and reduced shelf life of fruits. Overall, insect pollination increased the average commercial value of marketable fruits by 92%. The commercial value of hand-pollinated and open-pollinated strawberries did not differ. We conclude that pollination services are not merely important for yield, but also vital for physiological processes that result in better marketable quality (e.g. fruit appearance, flavour-enhancing constituents, prolonged shelf life) and commercial value of many pollinator-dependent crops.

Virus-Induced Gene Silencing of the Eggplant Chalcone Synthase Gene during Fruit Ripening Modifies Epidermal Cells and Gravitropism.

Eggplant ( Solanum melongena L.) fruits accumulate flavonoids in their cuticle and epidermal cells during ripening. Although many mutants available in model plant species, such as Arabidopsis thaliana and Medicago truncatula, are enabling the intricacies of flavonoid-related physiology to be deduced, the mechanisms whereby flavonoids influence eggplant fruit physiology are unknown. Virus-induced gene silencing (VIGS) is a reliable tool for the study of flavonoid function in fruit, and in this study, we successfully applied this technique to downregulate S. melongena chalcone synthase gene ( SmCHS) expression during eggplant fruit ripening. In addition to the expected change in fruit color attributable to a lack of anthocyanins, several other modifications, including differences in epidermal cell size and shape, were observed in the different sectors. We also found that silencing of CHS gene expression was associated with a negative gravitropic response in eggplant fruits. These observations indicate that epidermal cell expansion during ripening is dependent upon CHS expression and that there may be a relationship between CHS expression and gravitropism during eggplant fruit ripening.

IMPACT OF THE INTERACTION BETWEEN AMINO ACIDS (AA), NAPHTHALENE ACETIC ACID (NAA) AND NAPHTHALENE ACETAMIDE (NAD) ON SANTA ROSA PLUM FRUIT ABSCISSION, YIELD AND QUALITY.

To decrease fruit abscission, increase yield and improve fruit quality of Santa Rosa (Prunus salicina Lindl.) plum; amino acids (AA), naphthalene acetic acid (NAA) and naphthalene acetamide (NAD) and a combination of them were applied at different concentrations; at full bloom stage and one week after fruit setting stage during 2015 and 2016, in a private orchard at Ashmoun, Monofia governorate, Egypt. Results indicated that fruit set percentage significantly increased by all AA, NAA and NAD treatments compared to the control. AA 0.25 ml/L+NAA 10 ppm + NAD at 10 ppm recorded the highest significant fruit set percentage and the lowest significant fruit drop percentage and gave the maximum yield (62- 64 Kg/ tree). With regard to fruit quality, the same treatment increased fruit weight, length, diameter, firmness, pulp/stone ratio, and total soluble solids content, but decreased titratable acidity in Santa Rosa plum. In addition, total carbohydrates, total nitrogen, and C/N ratio in leaves were higher in treated trees than the control ones. Anatomical studies indicated that inactive embryo development after ovule fertilization may be the major cause of young fruit drop observed in ‘Santa Rosa’ plum trees. Furthermore, there was a relationship between physiological fruit drop which occurred from the middle of Growth Stage 2 to the beginning of Growth Stage 3, and seed development which contains inactive endosperm. From this study, it can be concluded that the combination of AA, NAA, and NAD increased fruit set, reduced fruit abscission, enhanced C/N ratio in leaves, and improved fruit yield and quality of Santa Rosa plum. Thus, it may be recommended to spray AA 0.25 ml/l +NAA 10 ppm + NAD 10 ppm under similar conditions

Application of growing degree days for mango hopper population dynamics at Lucknow, U.P.

Mango hopper population dynamics at different phenological stages was predicted using the growing degree days (GDD) of mango during 2013, 2014 and 2015 under Lucknow climatic conditions.Results revealed that at the time of flowering,there was wide variations in hopper infestation level during three consecutive seasons. Identical trend was observed at early flowering (30 per cent of panicle flowers open), full flowering (more than 50per cent of panicle flowers open), full flowering (all petals fallen or dry) and from fruit set to physiological fruit maturity. The relationship between the GDD and hopper population was established by linear regression analysis and it was inferred that the GDD had explained variation in hopper population upto 66 per cent across the three seasons. Thus, growing degree days served as a basis for predicting hopper population at different phenological stages of mango.

The Proteome of Fruit Peroxisomes: Sweet Pepper (Capsicum annuum L.) as a Model.

Despite of their economical and nutritional interest, the biology of fruits is still little studied in comparison with reports of other plant organs such as leaves and roots. Accordingly, research at subcellular and molecular levels is necessary not only to understand the physiology of fruits, but also to improve crop qualities. Efforts addressed to gain knowledge of the peroxisome proteome and how it interacts with the overall metabolism of fruits will provide tools to be used in breeding strategies of agricultural species with added value. In this work, special attention will be paid to peroxisomal proteins involved in the metabolism of reactive oxygen species (ROS) due to the relevant role of these compounds at fruit ripening. The proteome of peroxisomes purified from sweet pepper (Capsicum annuum L.) fruit is reported, where an iron-superoxide dismutase (Fe-SOD) was localized in these organelles, besides other antioxidant enzymes such as catalase and a Mn-SOD, as well as enzymes involved in the metabolism of carbohydrates, malate, lipids and fatty acids, amino acids, the glyoxylate cycle and in the potential organelles' movements.