Physiological Fruit Drop Research Articles

Limes physiological fruit drop extracts were incorporated into active packaging film for strawberry preservation

SummaryThe comprehensive utilisation of food waste has become a global development demand for enhancing their added value. This study aimed to develop and utilise physiological fruit drop of Citrus aurantium L. var Daidai with rich phenolic acids and flavonoids. Therefore, different concentrations (1%, 3%, 5%, 10% wt, based on pullulan weight) of daidai physiological fruit drop extracts (DE) were incorporated into pullulan/bacterial cellulose (BC) packaging film (PB2‐DE). The effects of different concentrations of DE on composite films were comprehensively evaluated. It was found that the mechanical properties, ultraviolet barrier properties, and antioxidant properties of the films were improved with the addition of DE. Moreover, application tests have verified that films containing DE can effectively maintain the attractive quality of strawberries. Conclusively, the results demonstrated the feasibility of DE incorporation into films to increase the value of the waste and the potential applicability of films containing DE in strawberry preservation.

The related research of flower bud differentiation and physiological fruit drop on ‘Soshu’ persimmon

The related research of flower bud differentiation and physiological fruit drop on ‘Soshu’ persimmon

Effect of shading and girdling on physiological fruit drop of Japanese persimmon ‘Akiou’

Effect of shading and girdling on physiological fruit drop of Japanese persimmon ‘Akiou’

Soil temperature and horticultural traits as influenced by mulching materials and orchard floor management practices in ber (Zizypus mauritiana Lamk.)


 Different type of mulches viz. paddy straw mulch (PSM), black polythene mulch (BPM), and white polythene mulch (WPM) were spreaded under the canopies of Indian ber (Zizypus mauritiana Lamk.) trees in second fortnight of October. The treatments of inter-cultivation (IC) and chemical weed management (CWM), and control trees were also kept for comparative analysis. The daily soil temperature recorded at 0900, 1200, 1400 and 1700 hours from October to April months during 2018-19 and 2019-20 revealed significant variations under different treatments. The respective soil temperature variation during 1st and 2nd year was minimum (9.2 and 9.9 oC) under PSM as compared to 16.5 oC in control plots throughout the investigation period. The soil temperature under PSM was higher during extreme winters whereas, it was comparatively lower during pre and post-winter season as compared to other treatments.The variations in intra-day average soil temperature during the months of October-November and again in March-April was higher than in December-February; the period of extreme winters. Significant reduction in physiological fruit drop was recorded under all the treatments with minimum fruit drop under PSM followed by BPM, while it was maximum in control trees. Likewise, fruit weight and fruit yield was also recorded highest under PSM followed by BPM treatments. The microbes in the rhizopshere of mulched trees with PSM followed by BPM exhibited highest and sustained activity from from Otober to April month under North-West Indian conditions.

제주 온주밀감 과실의 발육시기별 볼록총채벌레 피해증상

The damage of citrus caused by Scirtothrips dorsalis Hood is increasing in Jeju, Korea. The study about seasonal abundance of S. dorsalis in citrus orchards and occurrence of S. dorsalis in citrus influenced by adjacent primary host orchards has been conducted. However, study of injury symptoms caused by S. dorsalis in citrus is not clear. The symptoms are various according to seasons of occurrence and difficult to distinguish with other similar injury symptoms caused by citrus red mite, broad mite and citrus black spot disease. This study was conducted to distinguish the symptoms according to seasons of fruit stage and utilize for making strategy control S. dorsalis. The symptoms can be divided according to fruit stage. Symptom of full bloom stage was silver-white circle ankertrass around sepal and style of citrus. And symptom of 1st physiological fruit drop stage was that the area of silver-white circle was increased to inside and outside of circle around sepal and style of citrus. The symptom of 2nd physiological fruit drop stage was that the surface of damaged was suberized and cracked and transparent. At enlargement stage, rustic colored fruit was found and the symptom was generalized at coloring fruit stage. This result shows the symptoms caused by S. dorsalis on satsuma mandarin according to fruit stage and can be used as the basic data for studying control of S. dorsalis.

Comparative Study on Biological Characteristics and Fruit Quality Changes of Two Citrus Varieties

This experiment compared the phenophase, morphological features and fruit quality of the two citrus varieties. The results showed that the whole growth period of Lemon Siranui was about 12 days longer than Siranui. The flowering period, two physiological fruit drop periods and fruit color change period of Lemon Siranui were about 5-7 days later than Siranui. While this study illustrated differences in morphological features that Lemon Siranui tree was stronger than Siranui. And the fruit of Lemon Siranui was heavier than Siranui. It was clear to see that the percentages of soluble solids as well as vitamin C in Lemon Siranui were larger than those in Siranui, which led to better taste qualities. Overall, Lemon Siranui was a new high-quality strain citrus variety with excellent traits which was worth promoting from the analysis of appearance quality and nutritional quality.

Effects of elevated temperatures during the flowering to physiological fruit drop stage and at the fruit maturation stage on fruit quality of the satsuma mandarin

Effects of elevated temperatures during the flowering to physiological fruit drop stage and at the fruit maturation stage on fruit quality of the satsuma mandarin

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.

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.

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.

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

Daily Dynamics of Sugar and Phenol Contents in Apple Fruitlets during June Drop

The occurrence of the abscission signal in young developing fruits on apple trees (Malus domestica) was studied. Apple has a natural system of fruitlet shedding, so called June drop. Although physiological fruit drop is unable to guarantee production of marketable apples and avoid alternate bearing, knowledge of this is a key background for successful fruit thinning. A study was carried out on apple trees cv. ‘Golden Delicious’ during June drop. On three dates (beginning, middle and after June drop), the daily dynamics of HPLC detected individual sugar and spectrophotometrically detected total phenolic contents were investigated in central (K) and lateral (L) fruitlets. The results of daily dynamics showed the highest sugar contents at 2 p.m. On the final sampling date, on 2nd July 2015, we observed a significant difference between sugar contents at 2 p.m. and the morning and afternoon measurements. Contents of sugars in K and L fruitlets were not significantly different. Total phenolic content at the beginning of June drop was higher than at the end. There was no statistically significant difference between K and L in an individual time period, while there were statistically significant differences in total phenolic content among the sampling dates. Although sugar and phenolic contents in K and L fruitlets were rarely statistically different, their contents changed during June drop. In general, sugar contents increased and phenolic contents decreased during the process, while the daily dynamic depended on weather conditions.

Effects of Artificial Pollination and Grafting of Pollen Cultivar on Physiological Fruit Drop in ‘Soshu’ Persimmon

Effects of Artificial Pollination and Grafting of Pollen Cultivar on Physiological Fruit Drop in ‘Soshu’ Persimmon

Ca(NO3)2 canopy spraying during physiological fruit drop period has a better influence on the tree character and fruit quality of Newhall navel orange (Citrus sinensis Osbeck)

This study aimed to provide a theoretical basis for adopting suitable cultivation measures to tackle calcium (Ca) deficiency in citrus leaves. The Newhall navel orange (Citrus sinensis Osbeck) canopy was sprayed with 20.0 mmol L−1 of Ca(NO3)2 during physiological fruit drop period, fruit expanding period, and fruit maturing period on 30, 90, and 210 days after full bloom (DAFB), respectively, and its effects on leaf gas exchange parameters and leaf mineral nutrition and fruit quality were analyzed. The results showed that: (1) The photosynthetic rate (ACO2) at 9:00 a.m. and 16:00 p.m. of fruit expanding period with 30 and 90 DAFB Ca(NO3)2 treatments slightly or significantly improved mainly by decreasing stomatal limitation and nonstomatal limitation, respectively. (2) Compared with control (CK), the Ca concentration in leaves with 30, 90, and 240 DAFB Ca(NO3)2 treatments increased by 127.16, 97.53, and 33.33%, respectively, and the leaf magnesium concentration also increased by more than 32.26%. However, Ca(NO3)2 canopy spraying on 30 DAFB significantly reduced the leaf potassium concentration, by 22.14% compared with CK. (3) Ca(NO3)2 canopy spraying on 30 DAFB decreased the second fruit drop rate by 30.55% and increased the weight per fruit by 25.04%, thus resulting in a significant increase in citrus yield. (4) Spraying Ca(NO3) on 30 DAFB mainly affected the metabolism of titratable acid (TA) to improve the maturity of citrus fruits. Whilst it improved the external quality and the coloring of citrus fruit significantly. Therefore, Ca(NO3)2 canopy spraying during physiological fruit drop period has a better influence on the tree character and fruit quality of Newhall navel orange (Citrus sinensis Osbeck).

カンキツの早期生理落果における果実の離脱誘導と離脱特性

カンキツの早期生理落果における果実の離脱誘導と離脱特性

Efficacy of pre-harvest sprays to reduce rind pitting on Benny Valencia orange

Post-harvest pitting is a non-chilling related physiological rind disorder that the reduces external quality of various cultivars. The primary cause of post-harvest rind pitting of Valencia orange fruit is unknown, however, incidence thereof is aggravated by a change in post-harvest relative humidity (RH) and rind water status. The incidence of this disorder is erratic due to a wide range of factors influencing fruit susceptibility. Various plant growth regulators were evaluated to reduce the incidence of pitting in Benny Valencia fruit. Pre-harvest foliar sprays were performed in orchards during the 2014-2015 seasons in a complete randomised block design (n=10). The application of 2,4-D (2,4-dichlorophenoxyacetic acid, 10 mg L-1) at 50% petal drop or after physiological fruit drop reduced the incidence of post-harvest rind pitting by 38% and 56%, respectively. Application of s-abscisic acid (s-ABA, 400 mg L_1) (Protone) and thiabendazole (TBZ, 4000 mg L-1) (ICA-TBZ) 14 days before harvest reduced the incidence of this disorder by 43% and 51%, respectively. No negative effects of the foliar sprays in the form of chemical burn or loss of fruit quality were recorded. These results offer a new direction in the possible control of the incidence of this post-harvest physiological disorder by reducing susceptibility prior to harvest.

Anatomical Observations of the Citrus Fruit Abscission Zone and Morphological Changes of the Cells during Secondary Physiological Fruit Drop

Anatomical Observations of the Citrus Fruit Abscission Zone and Morphological Changes of the Cells during Secondary Physiological Fruit Drop

Cell wall related gene expression during secondary physiological fruit drop in ponkan (Citrus reticulataBlanco) and hyuganatsu (C. tamuranahort. ex Tanaka)

Physiological fruit drop in citrus is the deeper problem for fruit production and many researches have suggested that decreasing of carbohydrate translocation to fruit involved in fruit abscission. The fruit abscission process requires 3 stages for successful abscission, which include “induction”, “decision”, and “execution”. However, there is almost no information in the molecular mechanism of secondary physiological fruit drop in citrus. Here, anatomical observation and microarray analysis demonstrated the candidate genes involved in the fruit abscission process after induction of fruit abscission by incubating the detached ponkan (Citrus reticulata Blanco) and hyuganatsu (C. tamurana hort. ex Tanaka) fruit on agar medium. In our study, the cumulative ratio of fruit abscission was very high in ponkan, but very low in hyuganatsu. Morphology of abscission zone (AZ) cells was drastically changed in ponkan, but almost not changed in hyuganatsu. From the 60 K microarray analysis at 0, 12, 24, or 36 h after the induction, the specific up-regulated genes in ponkan AZ tissue were identified. The expressions of many cell wall degrading related genes, such as beta-galactosidase, polygalacturonase and beta-glucosidase etc. increased rapidly at 24 h. These results indicated that “execution” stage of fruit abscission process would be initiated until 24 h after the induction of fruit abscission in citrus.

Roles of Ethylene Production and Ethylene Receptor Expression in Regulating Apple Fruitlet Abscission.

Apple (Malus × domestica) is increasingly being considered an interesting model species for studying early fruit development, during which an extremely relevant phenomenon, fruitlet abscission, may occur as a response to both endogenous and/or exogenous cues. Several studies were carried out shedding light on the main physiological and molecular events leading to the selective release of lateral fruitlets within a corymb, either occurring naturally or as a result of a thinning treatment. Several studies pointed out a clear association between a rise of ethylene biosynthetic levels in the fruitlet and its tendency to abscise. A direct mechanistic link, however, has not yet been established between this gaseous hormone and the generation of the abscission signal within the fruit. In this work, the role of ethylene during the very early stages of abscission induction was investigated in fruitlet populations with different abscission potentials due either to the natural correlative inhibitions determining the so-called physiological fruit drop or to a well-tested thinning treatment performed with the cytokinin benzyladenine. A crucial role was ascribed to the ratio between the ethylene produced by the cortex and the expression of ethylene receptor genes in the seed. This ratio would determine the final probability to abscise. A working model has been proposed consistent with the differential distribution of four receptor transcripts within the seed, which resembles a spatially progressive cell-specific immune-like mechanism evolved by apple to protect the embryo from harmful ethylene.

Pre-harvest spray of oligochitosan induced the resistance of harvested navel oranges to anthracnose during ambient temperature storage

In this study, the ability of pre-harvest oligochitosan spray to control Colletotrichum gloeosporioides of navel orange during ambient temperature storage was examined. Navel orange trees were sprayed thrice with oligochitosan (15 g L−1 water) after physiological fruit drop. Results indicated that disease incidence and lesion diameter were lower in oligochitosan-treated fruit compared with the respective control. The inhibitory effects of volatiles in navel orange rind on the spore germination of C. gloeosporioides were significantly enhanced in the treated fruit compared with the control. Biochemical evaluations revealed that the contents of hydroxyproline-rich glycoprotein were increased. Protopectin degradation was delayed during storage. In addition, the activities of defense-related enzymes, including pectin methylesterase, peroxidase, chitinase, and phenylalanine ammonia-lyase, were increased in oligochitosan-treated navel orange fruit rinds. Our results suggested that pre-harvest oligochitosan spray can be a potential alternative to conventional control methods to prevent post-harvest anthracnose in navel orange.