scholarly journals Dikegulac Promotes Abscission in Citrus

HortScience ◽  
2004 ◽  
Vol 39 (7) ◽  
pp. 1655-1658 ◽  
Author(s):  
Luis Pozo ◽  
Ana Redondo ◽  
Ulrich Hartmond ◽  
Walter J. Kender ◽  
Jacqueline K. Burns
Keyword(s):  
Side Effects ◽  
Plant Growth ◽  
Plant Growth Regulator ◽  
Citrus Sinensis ◽  
Leaf Abscission ◽  
Application Time ◽  
Valencia Orange ◽  
Application Date ◽  
Orange Trees ◽  
Earlier Application

Two formulations of the plant growth regulator dikegulac (2,3:4,6-di-O-isopro-pylidene-α-L-xylo-2-hexulofuranosoic acid), consisting of dikegulac-sodium (Atrimmec) or dikegulac:ascorbic acid (1:1) (DAA), as well as 5-chloro-3-methyl-4-nitro-pyrazole at 200 mg·L-1, were applied as foliar sprays to `Hamlin' and `Valencia' orange trees (Citrus sinensis L. Osbeck) at two dates during the harvest season for each cultivar (11 Nov. and 10 Jan. for `Hamlin', 22 Mar. and 25 May for `Valencia'). Fruit detachment force was evaluated 10 days after application, whereas cumulative leaf abscission was monitored up to 60 days after application. In both cultivars, Atrimmec and DAA at 3,000 mg·L-1 induced moderate fruit loosening when applied at the earlier application date, but fruit loosening improved when applied at the later application date. In `Hamlin', both formulations caused higher leaf abscission when applied at the later date. DAA applications resulted in low leaf loss in `Valencia' regardless of application time, whereas Atrimmec caused unacceptably high leaf loss at either application date. No differences in internal fruit quality were found as a result of any abscission material treatment. The results indicate that DAA could be a promising option to induce fruit loosening in late harvested `Valencia' orange trees with minimal undesirable side effects.

scholarly journals Plant growth regulators on the pre-harvest period of 'Pêra' oranges

2008 ◽  
Vol 38 (3) ◽  
pp. 665-671 ◽  
Author(s):  
Isolina Maria Leite de Almeida ◽  
Elizabeth Orika Ono ◽  
João Domingos Rodrigues
Keyword(s):  
Plant Growth ◽  
Plant Growth Regulators ◽  
Growth Regulators ◽  
Growth Regulator ◽  
Orange Juice ◽  
Plant Growth Regulator ◽  
Citrus Sinensis ◽  
Juice Quality ◽  
Orange Trees

This research evaluated the effects of auxins and gibberellins applied at pre-harvest on the quality of orange juice. Orange trees, Citrus sinensis Osbeck, cv. 'Pêra' were sprayed in three applications, at 45-day intervals, with the following treatments: GA3 + 2,4-D at 12.5mg L-1 each; GA3 + 2,4-D at 25mg L-1; GA3 + 2,4-D at 37.5mg L-1; GA3 + NAA at 12.5mg L-1; GA3 + NAA at 25mg L-1; GA3 + NAA at 37.5mg L-1; NAA + 2,4-D at 12.5mg L-1; NAA + 2,4-D at 25mg L-1; NAA + 2,4-D at 37.5mg L-1, and a control. The treatments did not change juice quality, and showed no plant growth regulator residues 110 days after the last application in every case below 0.05mg L-1.

Sink strength of citrus rootstocks under water deficit

2021 ◽  
Author(s):  
Simone F da Silva ◽  
Marcela T Miranda ◽  
Vladimir E Costa ◽  
Eduardo C Machado ◽  
Rafael V Ribeiro
Keyword(s):  
Plant Growth ◽  
Root Growth ◽  
Water Deficit ◽  
Carbon Allocation ◽  
Sink Strength ◽  
Rangpur Lime ◽  
Carbon Supply ◽  
Valencia Orange ◽  
Source Sink ◽  
Orange Trees

Abstract Carbon allocation between source and sink organs determines plant growth and is influenced by environmental conditions. Under water deficit, plant growth is inhibited before photosynthesis and shoot growth tends to be more sensitive than root growth. However, the modulation of source-sink relationship by rootstocks remain unsolved in citrus trees under water deficit. Citrus plants grafted on Rangpur lime are drought tolerant, which may be related to a fine coordination of the source-sink relationship for maintaining root growth. Here, we followed 13C allocation and evaluated physiological responses and growth of Valencia orange trees grafted on three citrus rootstocks (Rangpur lime, Swingle citrumelo and Sunki mandarin) under water deficit. As compared to plants on Swingle and Sunki rootstocks, ones grafted on Rangpur lime showed higher stomatal sensitivity to the initial variation of water availability and less accumulation of non-structural carbohydrates in roots under water deficit. High 13C allocation found in Rangpur lime roots indicates this rootstock has high sink demand associated with high root growth under water deficit. Our data suggest that Rangpur lime rootstock used photoassimilates as sources of energy and carbon skeletons for growing under drought, which is likely related to increases in root respiration. Taken together, our data revealed that carbon supply by leaves and delivery to roots are critical for maintaining root growth and improving drought tolerance, with citrus rootstocks showing differential sink strength under water deficit.

Response of Tall Fescue (Festuca arundinacea) to Plant Growth Regulator Application Dates

1989 ◽  
Vol 3 (2) ◽  
pp. 408-413 ◽  
Author(s):  
Billy J. Johnson
Keyword(s):  
Plant Growth ◽  
Growth Regulators ◽  
Growth Regulator ◽  
Tall Fescue ◽  
Rapid Growth ◽  
Vegetative Growth ◽  
Festuca Arundinacea ◽  
Plant Growth Regulator ◽  
Growth Cycle ◽  
Application Date

Mon 4620 at 2.8 kg ai/ha, paclobutrazol plus mefluidide at 1.1 plus 0.4 kg ai/ha, and flurprimidol plus mefluidide at 1.1 plus 0.4 kg ai/ha were applied on four dates to determine their influence on highly maintained tall fescue turf. Seedhead suppression was good to excellent by Mon 4620 applied March 1 or 18 and by paclobutrazol plus mefluidide and flurprimidol plus mefluidide applied anytime from March 1 until April 1. None of the plant growth regulators (PGRs) suppressed seedheads effectively when applied April 15 when the grass was near the end of the rapid growth cycle and just before seedhead emergence. Vegetative growth of mowed tall fescue was suppressed for 8 weeks in 1987 when PGRs were applied March 1 immediately after full green-up. Application dates were not as important in 1988 as in 1987. Tall fescue was injured the least by Mon 4620 applied in March and by flurprimidol plus mefluidide applied on March 18. Paclobutrazol plus mefluidide injured the turf severely regardless of application date.

Laxogenosides Enhance Yield and Quality of Raphanus sativus L. Under Greenhouse Condition

2021 ◽  
Vol 15 (4) ◽  
pp. 542-547
Author(s):  
Jinna Liu ◽  
Zihe Zha ◽  
Xiaoli Liu ◽  
Cunli Zhang
Keyword(s):  
Plant Growth ◽  
Growth Regulator ◽  
Plant Growth Regulator ◽  
Raphanus Sativus ◽  
Water Soluble ◽  
The Other ◽  
Application Time ◽  
Greenhouse Experiments ◽  
Yield And Quality

Laxogenoside-C (LG-C) has BRs-likely activity and with higher activity stability. In this study, the LG-C and SsS (the mixture of Laxogenoside-A, -B, and -C; isolated from the Smilax scobinicaulis C.H. Wright) were used to conduct the seeding treatment and greenhouse experiments with different application time and concentrations, to clarify the effect on yield and quality of radish (Raphanus sativus L.) for development of a new plant growth regulator. The results showed that 10 μM LG-C and SsS increased hypocotyls, elongation and cotyledon weight compared with other treatment. The greenhouse experiments indicated that the interaction effect of plant growth regulator types and application time was significant for all parameters except for phosphorus content. An application of LG-C or SsS produced a higher yield than multiple times. Compared with T0 treatment, LG-C and SsS sprayed at root enlargement (T4) increased yield by 25.33% and 24.10%, respectively. T4 treatment of LG-C produced the highest yield and free amino acid and phosphorus, but the other parameters not. T4 treatment of SsS not only had the highest yield and water-soluble carbohydrates and water-soluble protein but also improved the other radish quality. In conclusion, this study indicated that the application of SsS at root enlargement with 10 μM improved radish root tubers yield and quality.

scholarly journals 179 Impact of Rootstock on Maturity and Storage of Valencia Orange Fruits

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 421D-421
Author(s):  
M.M. Khattab ◽  
A.A. Elezaby ◽  
S. ElOraby ◽  
A.M. Hassan
Keyword(s):  
Citrus Sinensis ◽  
Poncirus Trifoliata ◽  
Maturity Stage ◽  
Full Bloom ◽  
Valencia Orange ◽  
Volkamer Lemon ◽  
Orange Trees ◽  
And Storage ◽  
Cleopatra Mandarin ◽  
Troyer Citrange

This investigation was carried out on 13-year-old Valencia orange trees [Citrus sinensis (L.) Osbeck] budded on five different rootstocks. Heat unit accumulation (temperature above 12.5 °C) for fruits worked on the various rootstocks were calculated from full bloom to maturity stage. Valencia fruits on Troyer citrange (C. sinensis × Poncirus trifoliata) and Carrizo citrange (C. sinensis × Poncirus trifoliata) rootstocks matured earlier when compared to those growing on Cleopatra mandarin (C. reticulata Blanco), Volkamer lemon (C. volkameriana Ten. and Pasq.), and sour orange (C. aurantium) rootstocks. The results showed that the Valencia fruits, regardless of rootstock, could be stored for different periods under different conditions. However, in order to avoid degradation in fruit quality, storing periods should not exceed 21, 60, and 120 days under room conditions (25 °C and RH 25% to 35%), 4 °C (RH 80% to 85%), and 8 °C (RH 80% to 85%); respectively.

scholarly journals Uptake Patterns of 11 Elements of Orange Trees in Solution Culture

HortScience ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 486B-486
Author(s):  
H.K. Wutscher
Keyword(s):  
Nutrient Solution ◽  
Citrus Sinensis ◽  
Soil Extract ◽  
Solution Culture ◽  
Field Soil ◽  
Rough Lemon ◽  
Valencia Orange ◽  
Orange Trees ◽  
Solution Change ◽  
Complete Nutrient Solution

Three trees each of `Valencia' orange (Citrus sinensis L. Osbeck) on rough lemon (C. limon L. Burm. f.) rootstocks that had been grown in solution culture since July 1989 were grown in two solutions from Oct. 1995 to Sept.1996. Solution 1 was a soil extract made by boiling field soil (1:2 soil:water) for 20 min and filtering. Solution 2 was a complete nutrient solution. The solutions were analyzed every 7 days and changed every 28 days. At each solution change, the newly prepared solutions were analyzed for 11 elements and their depletion was determined by weekly analysis. Nearly all the N, K, and Mn in Solution 1 was absorbed in the first 7 days after each solution change; in Solution 2, N and Mn were also absorbed in 7 days, but K absorption was variable; single trees sometimes needed 4 weeks to absorb all the potassium. Calcium and Mg were never completely absorbed and in contrast to Mn, traces of Fe, Zn, and Cu remained in both solutions after 4 weeks.

scholarly journals Late-season `Valencia' Orange Mechanical Harvesting with an Abscission Agent and Low-frequency Harvesting

HortScience ◽  
2006 ◽  
Vol 41 (3) ◽  
pp. 660-663 ◽  
Author(s):  
Jacqueline K. Burns ◽  
Fritz M. Roka ◽  
Kuo-Tan Li ◽  
Luis Pozo ◽  
Richard S. Buker
Keyword(s):  
Citrus Sinensis ◽  
Low Frequency ◽  
Mature Fruit ◽  
Fruit Removal ◽  
Immature Fruit ◽  
Late Season ◽  
Valencia Orange ◽  
Significant Difference ◽  
Orange Trees

An abscission agent (5-chloro-3-methyl-4-nitro-1H-pyrazole [CMNP]) at 300 mg·L–1 in a volume of 2810 L·ha–1 was applied to Valencia orange trees [Citrus sinensis (L.) Osb.] on 22 May 2004. At this time, immature and mature fruit were present on the tree simultaneously. Three days after application, fruit were mechanically harvested using a trunk-shake-and-catch system. The power to the shaker head was operated at full- or half-throttle (FT or HT, respectively), and the duration of trunk shaking was 2 seconds at FT or 4 seconds at FT and HT. Mature fruit removal percentage and number of immature fruit removed, and fruitlet weight and diameter were determined. Mature fruit removal percentage with 2 seconds at FT or 4 seconds at FT harvesting ±CMNP, or 4 seconds at HT + CMNP was not significantly different and ranged between 89% to 97%. Harvesting at 4 seconds HT without CMNP removed significantly less mature fruit than any treatment. CMNP did not affect immature fruit removal by the trunk shaker. Harvesting at 4 seconds at HT removed significantly less immature fruit than 2 seconds at FT or 4 seconds at FT. No significant difference in fruitlet weight or diameter was measured between any trunk shaker harvest operation and CMNP treatment. Trunk shaking frequency was estimated to be 4.8 and 8.0 Hz at HT and FT, respectively. Yield in 2005 was determined on the same trees used for harvest treatments in 2004. CMNP did not impact yield. No significant difference in yield was seen between the hand-picked control and 4 seconds at HT, whereas yield in the remaining treatments was lower. The results demonstrate that CMNP application combined with low frequency trunk shaker harvesting can achieve high percentage of mature fruit removal with no significant impact on return yield of the following crop.

scholarly journals Effect of Annual Defoliation on Yield, Juice Quality, Leaf Net Gas Exchange, Leaf Size, and Number in `Hamlin' and `Valencia' Orange Trees

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1146B-1146
Author(s):  
Rongcai Yuan ◽  
Francisco Garcia-Sanchez ◽  
Fernando Alferez ◽  
Igor Kostenyuk ◽  
Shila Singh ◽  
...  
Keyword(s):  
Leaf Area ◽  
Citrus Sinensis ◽  
Leaf Size ◽  
Fruit Weight ◽  
Fruit Yield ◽  
Soluble Solids ◽  
Juice Quality ◽  
Valencia Orange ◽  
Acid Ratio ◽  
Orange Trees

The effect of annual defoliation over two consecutive years on fruit yield, juice quality, leaf size, and number was examined in 11-year-old `Hamlin' and 13-year-old `Valencia' orange [Citrus sinensis (L.) Osb.] trees. Removal of up to 50% of the leaves in late November had no effect on fruit number, fruit weight, fruit yield, soluble solids yield, juice °Brix, and °Brix: acid ratio of juice in `Hamlin' oranges. In `Valencia' oranges, removal of up to 50% of the leaves in late March also did not affect °Brix or the °Brix: acid ratio of the juice, but decreased fruit yield and soluble solids yield. Leaf size was reduced by removal of 50% of the leaves in both cultivars. Removal of up to 50% leaves in late November had no significant influence on net CO2 assimilation (aCO2) of the subsequent spring flush leaves in early May in `Hamlin' oranges, whereas aCO2 of `Valencia' spring flush leaves in early May increased linearly with increasing levels of defoliation in late March. The results indicate that fruit yield, fruit quality, leaf size, and number were not negatively impacted when annual defoliations did not exceed 25% of the total canopy leaf area for `Valencia' and `Hamlin' oranges for two consecutive years. Overall, in whole `Hamlin' or `Valencia' orange trees, fruit weight increased linearly with increasing ratio of leaf area to fruit, suggesting that fruit enlargement depends on available photosynthate and can be limited by leaf area.

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