Shoot and Root Growth of Lettuce Seedlings Following Root Pruning

Biddington, N. L.; Dearman, A. S.

doi:10.1093/oxfordjournals.aob.a086731

Cited by 13 publications

(11 citation statements)

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“…3) increased for roots in response to root excision, whereas it decreased slightly for shoots; but this decrease was only clearly apparent at the two most severe cutting levels. This behaviour, which agrees with previous reports (Humphries, 1958;Buttrose and Mullins, 1968;Richards and Rowe, 1977a;Biddington and Dearman, 1984), was observed whatever the initial plant weight. During the following time course, both specific growth rates approximately regained the values observed before cutting (Figs 1 and 3 A).…”

Section: Resultssupporting

confidence: 93%

“…During vegetative growth preceding excision (measured accurately only at 25 °C), the root fraction decreased slightly with time, as usually observed under non-limiting growth conditions (Bray, 1963;Troughton, 1967;Caloin and Yu, 1984). Immediately after cutting, the percentage of roots increased and attained a maximum close to its initial value (Brouwer, 1962;Biddington and Dearman, 1984). This maximum should indicate the end of the perturbed phase since, in the growth which followed, the root fraction again exhibited the decrease characteristic of unperturbed vegetative growth.…”

Section: Resultsmentioning

confidence: 58%

“…Following root excision, no significant wilting effect was observed for shoots. However, a partial wilting cannot be excluded for excised roots which ceased elongating due to the removal of terminal apices (Biddington and Dearman, 1984).…”

Section: Methodsmentioning

confidence: 99%

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Regrowth Kinetics of Dactylis glomerata Following Root Excision

Caloin

Clement²,

Herrmann³

1991

Annals of Botany

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The growth kinetics of Dactylis glomerata following a root excision were studied in order to characterize the process of partitioning of carbon assimilates between shoots and roots. Plants were grown hydroponically, in constant environments. The variations with time of shoot and root fresh weights during regrowth were measured using a nondestructive method. The effect of root excision on shoot and root water contents was also determined from complementary experiments. Immediately after cutting, the specific growth rate increased markedly for roots and decreased slightly for shoots, but this decrease can be at least partly accounted for by the variation of the shoot water content. At the end of the perturbed phase, the specific growth rates and the root fraction had almost returned to the values measured immediately before cutting. The experimental regrowth kinetics were analysed in terms of a kinetic model which calculates shoot and root growth as the difference between the carbon provided by photosynthesis and carbon losses associated with respiration. A satisfactory description of the regrowth kinetics was obtained by assuming that the partitioning of carbon substrates between shoots and roots is not modified by cutting, and that the partitioning coefficient remains constant during regrowth. According to this analysis, the stimulation of root growth after cutting can be mainly attributed to the reduction in the part of carbon substrates utilized in roots for maintenance requirements.

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Section: Resultssupporting

confidence: 93%

Section: Resultsmentioning

confidence: 58%

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Regrowth Kinetics of Dactylis glomerata Following Root Excision

Caloin

Clement²,

Herrmann³

1991

Annals of Botany

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“…In Western Europe, field-grown lettuce crops are established from transplants raised in compact peat blocks in greenhouses; because seeds germinate faster and more uniformly in peat blocks than in the field, transplanted crops are more competitive toward early weed infestation (Maltais et al, 2008) and provide a more uniform stand, thus facilitating crop scheduling (Cattivello and Danielis, 2008), reducing cropping time and allowing more plantings per year in the same field. However, transplanting induces a major stress in lettuce cultivation: lettuce seedlings in the optimal stage for transplanting (5–7 leaf stage) often suffer from mechanical root pruning (decapitation of the root tip; Biddington and Dearman, 1984) when seedlings are pulled out of the tray. The loss of root tips and root hairs due to root pruning at transplanting disturbs the root:shoot ratio and induces a “recovery phase” during which shoot growth is suppressed until the previous root:shoot ratio is restored (Bar-Tal et al, 1994a).…”

Section: Introductionmentioning

confidence: 99%

Influence of transplant size on the above- and below-ground performance of four contrasting field-grown lettuce cultivars

Kerbiriou¹,

Stomph²,

Bueren³

et al. 2013

Front. Plant Sci.

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Background and aims: Modern lettuce cultivars underperform under conditions of variable temporal and spatial resource availability, common in organic or low-input production systems. Information is scarce on the impact of below-ground traits on such resource acquisition and performance of field-grown lettuce; exploring genetic variation in such traits might contribute to strategies to select for robust cultivars, i.e., cultivars that perform well in the field, even under stress.Methods: To investigate the impact of below-ground (root development and resource capture) on above-ground (shoot weight, leaf area) traits, different combinations of shoot and root growth were created using transplants of different sizes in three field experiments. Genetic variation in morphological and physiological below- and above-ground responses to different types of transplant shocks was assessed using four cultivars.Results: Transplanting over-developed seedlings did not affect final yield of any of the four cultivars. Small transplant size persistently impacted growth and delayed maturity. The cultivars with overall larger root weights and rooting depth, “Matilda” and “Pronto,” displayed a slightly higher growth rate in the linear phase leading to better yields than “Mariska” which had a smaller root system and a slower linear growth despite a higher maximal exponential growth rate. “Nadine,” which had the highest physiological nitrogen-use efficiency (g dry matter produced per g N accumulated in the head) among the four cultivars used in these trials, gave most stable yields over seasons and trial locations.Conclusions: Robustness was conferred by a large root system exploring deep soil layers. Additional root proliferation generally correlates with improved nitrate capture in a soil layer and cultivars with a larger root system may therefore perform better in harsh environmental conditions; increased nitrogen use efficiency can also confer robustness at low cost for the plant, and secure stable yields under a wide range of growing conditions.

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“…It reflects a relationship between the processes of growth and development of plant organs and suggests a mechanism that maintains a balance between shoot and root growth. Thus, after the excision of a considerable part of roots in various plant species, the growth of the root system was activated [3,4]; this process requires a redistribution of assimilates in favor of roots. It is still unknown how plants control biomass accumulation by their underground and aboveground organs.…”

Section: Introductionmentioning

confidence: 99%

Mechanisms Coordinating Wheat Seedling Growth Response as Affected by Shoot/Root Ratio

Vysotskaya

2005

Russ J Plant Physiol

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Excision of four out of five roots in 7-day-old wheat seedlings ( Triticum durum Desf.) rapidly suppressed shoot growth promoted biomass accumulation by the remained root largely due to its expanded branching. Next, the rate of shoot growth increased although was not completely recovered. After the reduction of the root system, the rate of photosynthesis in the leaves of seedlings did not decrease. As compared to the intact plants, auxins and cytokinins accumulated in the remained root, whereas in the growing part of the shoot, the level of auxins rapidly declined. Shoot growth rate was assumed to decrease after the excision of a part of the root system due to lower extensibility of growing tissue, and the promotion of lateral root formation on the remained root apparently resulted from active redistribution of phytohormones and assimilates between plant organs. The prime role of hormonal signals in the coordination of shoot and root growth is discussed.

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Shoot and Root Growth of Lettuce Seedlings Following Root Pruning

Cited by 13 publications

References 0 publications

Regrowth Kinetics of Dactylis glomerata Following Root Excision

Regrowth Kinetics of Dactylis glomerata Following Root Excision

Influence of transplant size on the above- and below-ground performance of four contrasting field-grown lettuce cultivars

Mechanisms Coordinating Wheat Seedling Growth Response as Affected by Shoot/Root Ratio

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