scholarly journals 531 CMN-Pyrazole-induced Abscission of Mature `Valencia' Oranges in Relation to Young Fruit, Root, and Shoot Growth

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 487A-487
Author(s):  
Rongcai Yuan ◽  
Ulrich Hartmond ◽  
Walter J. Kender

The seasonal abscission response of mature `Valencia' oranges [Citrus sinensis (L.)Osb.] to 5-chloro-3-methyl-4-nitro-1H-pyrazole (CMN-Pyrazole) was examined in relation to young fruit, shoot, and root growth. CMN-Pyrazole dramatically increased ethylene production in fruit and effectively reduced the fruit detachment force (FDF), except in a period of reduced response to CMN-Pyrazole in early May. Root growth was inhibited by trunk girdling, in combination with removal of spring vegetative flushes and flowers, but not by their removal alone. During the responsive period, there was no difference in both ethylene production and FDF of CMN-Pyrazole-treated mature oranges between 1) the unmanipulated trees and those manipulated by either 2) girdling, removal of spring flushes and flowers, or 3) removal of flushes and flowers alone. However, during the less-responsive period, ethylene production in CMN-Pyrazole-treated mature oranges was significantly lower while the FDF was higher from non-manipulated trees than from trees treated by either girdling and removal of flush, or only removal of flush. There was no difference in either ethylene production or FDF of CMN-Pyrazole-treated mature oranges between trees manipulated by girdling and removal of flush, and those by removal of flush alone. Flush growth terminated at least 2 weeks before the onset of the less responsive period. This suggests that the hormones from rapidly growing young fruit may be responsible for the less responsive period.

2001 ◽  
Vol 126 (4) ◽  
pp. 414-419 ◽  
Author(s):  
Rongcai Yuan ◽  
Ulrich Hartmond ◽  
Angela Grant ◽  
Walter J. Kender

Influence of young fruit, shoot, and root growth on response of mature `Valencia' oranges [Citrus sinensis (L.) Osbeck] to the abscission chemical CMN-pyrazole was examined in 1999 and 2000. CMN-pyrazole dramatically increased ethylene production in mature fruit and reduced the fruit detachment force (FDF), except during a period of reduced response to CMN-pyrazole in early May when spring vegetative growth, young fruit of the following year's crop, and mature fruit were all on the trees. Removal of spring flushes, which included spring vegetative shoots and leafy and leafless inflorescences, prevented any young fruit and shoot growth, but did not inhibit root growth. However, trunk girdling in combination with removal of spring flushes not only prevented growth of young fruit and shoots but also inhibited root growth. During the responsive period, there were no differences in either ethylene production or FDF of CMN-pyrazole-treated mature oranges between 1) the nonmanipulated trees and those manipulated by either 2) removal of spring flushes alone, or 3) in combination with trunk girdling. However, during the less responsive period, ethylene production in CMN-pyrazole-treated mature oranges was significantly lower while the FDF was higher in nonmanipulated trees than in trees treated by either removal of spring flushes alone, or in combination with trunk girdling. There was no difference in either fruit ethylene production or FDF between trees manipulated by (2) removal of spring flushes alone, and (3) removal of spring flushes in combination with trunk girdling regardless of CMN-pyrazole application. Shoot growth terminated at least 2 weeks before the onset of the less responsive period. Removal of young fruit increased response of mature fruit to CMN-pyrazole during the less responsive period. This suggests that hormones from rapidly growing young fruit may be responsible for the occurrence of the less responsive period. Chemical name used: 5-chloro-3-methyl-4-nitro-1H-pyrazole (CMN-pyrazole).


1990 ◽  
Vol 8 (1) ◽  
pp. 10-13
Author(s):  
Rita L. Hummel ◽  
Charles R. Johnson ◽  
Orville M. Lindstrom

Abstract Rooted liners of Kalmia latifolia L. ‘Elf’, ‘Freckles’ and ‘Goodrich’ were shipped to Griffin, Georgia, and Puyallup, Washington and were potted into 3.8 liter (# 1) containers. Factorial combinations of growing media (1 bark: 1 peat, 4 bark: 1 peat), NO3/NH4 ratios (100% NO3/0% NH4, 60% NO3/40% NH4, 20% NO3/80% NH4), and rates of N (40, 80, and 120 mg N/pot; 0.0014, 0.0028, and 0.0042 oz N/pot, resp.) were applied at both locations. Results indicated that a combination of the nitrate/ammonium forms of nitrogen (60/40 NO3/NH4) and the 80 mg/pot N rate produced the best overall shoot and root growth on all 3 cultivars at both locations. Root and shoot growth was not affected by growing media at either location. With the exception of lower pH readings for the Georgia media, results for the two locations were remarkably consistent.


1995 ◽  
Vol 120 (2) ◽  
pp. 211-216 ◽  
Author(s):  
J. Roger Harris ◽  
Nina L. Bassuk ◽  
Richard W. Zobel ◽  
Thomas H. Whitlow

The objectives of this study were to determine root and shoot growth periodicity for established Fraxinus pennsylvanica Marsh. (green ash), Quercus coccinea Muenchh. (scarlet oak), Corylus colurna L. (Turkish hazelnut), and Syringa reticulata (Blume) Hara `Ivory Silk' (tree lilac) trees and to evaluate three methods of root growth periodicity measurement. Two methods were evaluated using a rhizotron. One method measured the extension rate (RE) ofindividual roots, and the second method measured change in root length (RL) against an observation grid. A third method, using periodic counts of new roots present on minirhizotrons (MR), was also evaluated. RE showed the least variability among individual trees. Shoot growth began before or simultaneously with the beginning of root growth for all species with all root growth measurement methods. All species had concurrent shoot and root growth, and no distinct alternating growth patterns were evident when root growth was measured by RE. Alternating root and shoot growth was evident, however, when root growth was measured by RL and MR. RE measured extension rate of larger diameter lateral roots, RL measured increase in root length of all diameter lateral roots and MR measured new root count of all sizes of lateral and vertical roots. Root growth periodicity patterns differed with the measurement method and the types of roots measured.


Weed Science ◽  
1981 ◽  
Vol 29 (6) ◽  
pp. 697-703 ◽  
Author(s):  
Michael Barrett ◽  
Floyd M. Ashton

Napropamide [2-(α-napthoxy)-N,N-diethylpropionamide] inhibited root and shoot growth in corn (Zea maysL. ‘NC+ 59’) and tomato (Lycopersicon esculentumMill. ‘Niagara VF315’) seedlings. Shoot growth was reduced less than root growth in both species. Corn roots were approximately 10 times more sensitive to napropamide than were tomato roots. Translocation of napropamide from the roots to the shoot of tomato occurred within 0.5 h and followed an apoplastic pattern. Little movement of napropamide from the roots to the shoots occurred in corn. Metabolism of napropamide was not evident in either species during an 8-h exposure. Absorption studies showed that total napropamide levels were 60% higher in corn root tissue than in tomato root tissue. The greater napropamide content in the corn roots was associated with a tightly bound fraction of the total napropamide influx.


2020 ◽  
pp. 1443-1448
Author(s):  
Caroline Beal Montiel ◽  
Deonir Secco ◽  
Araceli Ciotti Marins ◽  
Luiz Antônio Zanão Junior ◽  
Jeikson Rafael Deggerone ◽  
...  

Soil compaction, induced by no-tillage practices, can negatively impact soil properties important for plant growth. Compacted soils can restrict root growth depth, resulting in reduced crop yield. Although safflower (Carthamus tinctorius) has a deep root system, yield may still be affected by soil compaction. Therefore, this study aimed to evaluate safflower root and shoot growth when submitted to soil compaction in an Oxisol soil under controlled (greenhouse) and field conditions. Five soil bulk density measures were performed in a greenhouse (1.1, 1.2, 1.3, 1.4 and 1.5 Mg m–3). Four compaction levels (established by the number of passes of a farm tractor: 0, 1, 3, and 5 passes consecutively) were performed to evaluate the effect of soil compaction in the field. Root and shoot growth were measured after harvesting the plants. Safflower root growth was reduced when soil compaction increased from 1.1 to 1.5 Mg m–3 under controlled (greenhouse) conditions. In field conditions, we observed a decrease in root length, and fresh and dry matter in roots and shoots of safflower as the soil compaction increased to 5P (1.28 Mg m–3). The results of our study suggest safflower root and shoot growth can be impacted by soil compaction which could affect crop yield.


HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 481e-481
Author(s):  
Susan D. Day ◽  
Nina L. Bassuk

Four techniques for compaction amelioration were studied: 1) Vertical drainage panels; 2) vertical gravel-filled sump drains; 3) soil trenches filled with sandy loam; and 4) peat amended back fill. The control was backfilled with existing soil on the site. Vertical drainage mats and vertical gravel-filled sump drains were shown to increase O2% in surrounding soil; however, all O2 levels regardless of treatment were above what is considered limiting. Shoot and root growth of Pyrus calleryana `Redspire' was greatest for treatments that alleviated mechanical impedance (soil trenches and amended back fill) and least for treatments that did not (controls and vertical drains). Vertical drainage mats which alleviated mechanical impedance to a lesser degree showed intermediate growth.


1999 ◽  
Vol 9 (1) ◽  
pp. 131
Author(s):  
Timothy K. Broschat

Royal palms [Roystonea regia (HBK.) O.F. Cook], coconut palms (Cocos nucifera L. `Malayan Dwarf'), queen palms [Syagrus romanzoffiana (Chamisso) Glassman], and pygmy date palms (Phoenix roebelenii O'Brien) were grown in a rhizotron to determine the patterns of root and shoot growth over a 2-year period. Roots and shoots of all four species of palms grew throughout the year, but both root and shoot growth rates were positively correlated with air and soil temperature for all but the pygmy date palms. Growth of primary roots in all four species was finite for these juvenile palms and lasted for only 5 weeks in royal palms, but ≈7 weeks in the other three species. Elongation of secondary roots lasted for only 9 weeks for coconut palms and less than half of that time for the other three species. Primary root growth rate varied from 16 mm·week-1 for coconut and pygmy date palms to 31 mm·week-1 for royal palms, while secondary root growth rates were close to 10 mm·week-1 for all species. About 25% of the total number of primary roots in these palms grew in contact with the rhizotron window, allowing the prediction of the total root number and length from the sample of roots visible in the rhizotron. Results indicated that there is no obvious season when palms should not be transplanted in southern Florida because of root inactivity.


1970 ◽  
Vol 19 (2) ◽  
pp. 119-128
Author(s):  
AHMZ Ali

In a phytotron chamber the effect of mechanical impedance on root and shoot growth of BR?29 variety of rice at different time intervals reaveled that length of the seminal axis and length of the longest leaf extended linearly in both unimpeded and impeded treatments. Diameter of roots increased in impeded treatment. The number of first order laterals also increased linearly with time in both unimpeded and impeded treatments. Although there were always significantly more laterals on the unimpeded root axes, lateral spacing does not show any tendency to change with time. Root growth rate was nearly half in impeded than in unimpeded treatment. The pattern of root length in unimpeded (UI) did not differ from that of the pattern in impeded (I) treatment as the ratios (I/UI) were more or less constant with time. The time of leaf appearance was delayed by one ? two days and leaf growth period was shortened by one day in impeded than in unimpeded treatment. Leaf growth rates did not differ significantly between day and night time although night time growth rates were always slightly less than day time. Key words: Mechanical impedance; Pattern of root growth; Time interval; Shoot growth; Rice DOI: http://dx.doi.org/10.3329/dujbs.v19i2.8953 DUJBS 2010; 19(2): 119-128


Weed Science ◽  
1986 ◽  
Vol 34 (2) ◽  
pp. 225-232 ◽  
Author(s):  
Leonie B. Nadeau ◽  
Ian N. Morrison

Shoot and root growth of green foxtail [Setaria viridis(L.) Beauv. # SETVI] and yellow foxtail [Setaria lutescens(L.) Beauv. # SETLU] were compared under three moisture regimes under simulated field conditions in 1982 and 1983. An increase in water supply from 0.3 to 2.5 cm/week resulted in proportionately greater increases in the number of tillers and leaf area of green foxtail compared to yellow foxtail. In 1982, green foxtail produced approximately three times as many seed as yellow foxtail under all three water regimes, whereas under warmer conditions in 1983, green foxtail produced nearly six times as many seed as yellow foxtail under the highest water regime and more than 11 times under the lowest regime. By using a specially constructed periscope to observe root growth through clear plastic tubes implanted in the soil it was determined that the amount of available moisture had much less effect on root growth than on shoot growth of the two species. In 1982, green foxtail tended to produce more roots than yellow foxtail early in the season but as the plants matured no significant differences occurred between species. In 1983, no significant differences in total root length occurred between species at any growth stage. The roots of both species penetrated to a depth of nearly 60 cm, with the highest concentration of roots occurring at depths of 20 to 30 cm.


1992 ◽  
Vol 43 (5) ◽  
pp. 1169 ◽  
Author(s):  
LD Osborne ◽  
AD Robson

The duration of inhibition of zinc uptake by chlorsulfuron was examined in wheat plants in a glasshouse experiment. Chlorsulfuron decreased shoot weight, root weight and zinc uptake. Plants that were treated with chlorsulfuron and adequately supplied with zinc partially recovered from root and shoot growth inhibition by 6 weeks and zinc uptake was recovering by 8 weeks. Plants that were seriously zinc deficient did not recover. In this experiment, potential grain yield was only reduced by chlorsulfuron when zinc supplies were inadequate. It is suggested that the recovery of plants from zinc deficiency may be the result of two processes; hydrolysis of chlorsulfuron with time removing constraints to root growth and functioning, and the release of root exudates from zinc deficient plants effective at mobilizing zinc from soil. In the field, chlorsulfuron is only likely to induce zinc deficiency and reduce yield in wheat where supplies of this trace element are marginal for growth.


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