Shedding of Roots

Head, G. C.

doi:10.1016/b978-0-12-424250-0.50012-9

Cited by 50 publications

(18 citation statements)

References 55 publications

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“…Using root-observation boxes or trenches in which individual 'pioneer" roots in the soil were viewed with glass windows, several investigators have indicated that pioneer roots of greater diameter have more rapid extension rates than those of smaller diameter (Mason, Bhar & Hitton, 1970;Kozlowski, 1971;Head, 1973). Presumably, the root tips of large-diameter roots (> 2 mm) are strong sinks for available photosynthates.…”

Section: Discussionmentioning

confidence: 99%

On the relationship between specific root length and the rate of root proliferation: a field study using citrus rootstocks

1991

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SUMMARYThis study tested two hypotheses: (1) species with roots that have a high length to dry mass ratio or specific root length (SRL) also have the potential for high rates of root growth in small volumes of favourable soil and (2) variation in average root diameter fully accounts for variation in SRL. To minimize differences among shoots, the study used 13-year-old 'Valencia' sweet orange [Citrus sinensis (L.) Osbeck] trees budded to rootstocks representing a range of genotypes. Soil cores 7-4 cm in diameter and 14-2 cm deep were extracted from beneath the canopy, and the soil was sieved free of roots and replaced. Root length, diameter and dry weight of the roots in the disturbed soil and adjacent undisturbed soil were evaluated 5, 10, 19 and 40 weeks following soil replacement. The disturbed soil had a higher water content than the undisturbed soil for the Hrst three sampling dates. Averaged across rootstocks, root length density increased in a linear fashion in the disturbed soil and was comparable to that in the undisturbed soil by 40 weeks. Mean root diameter of the fibrous roots ( < 2 mm) declined with age. Rootstocks with the highest SRL had the most rapid rate of root proliferation (cm cm"^ wk"^) (r = 0-94) and the greatest rate of water extraction at 19 weeks (r = 0 79). Although variation in root diameter contributed to rootstock variation in SRL, the data also suggested that rootstocks of high SRL had roots with lower tissue density than those of low SRL {P < O'OS). The potential trade-offs of constructing root systems of high SRL are discussed.

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Section: Discussionmentioning

confidence: 99%

On the relationship between specific root length and the rate of root proliferation: a field study using citrus rootstocks

1991

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“…Head (1973) notes the shedding of woody roots by perennials is greater in winter. Our samples were taken in winter and it is likely the values of root length would have been higher had they been taken in summer.…”

Section: Discussionmentioning

confidence: 99%

Distribution of grapevine roots and salt under drip and full-ground cover microjet irrigation systems

Stevens

Douglas²

1994

Irrig Sci

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We describe the three dimensional variation in root length density (Lv) within a quarter of the planting area of Colombard grapevines on Ramsey rootstock grown under drip and full-cover microjet irrigation. Under drip irrigation roots were concentrated under the vine row, whereas under microjet irrigation roots were evenly spread across the ~planting area. The maximum L v were 1.2 and 0.6 cm/cm-' and the estimated total root lengths per vine were 32 and 26 km for drip and microjet irrigated vines, respectively. Under drip irrigation, 56% of the variation in Lv could be accounted for as a function of depth and radial distance into the row, and under microjet, 45% of the variation in L v could be accounted for as a function of depth. Twenty five per cent of the vine roots were in soil with an air filled porosity at field capacity of 6% or less. Based on the variation of root length per unit area (La) across a quarter of the planting area and between vines, we concluded that selection of a location at which the L a would be representative of that in the entire irrigation unit is feasible in microjet irrigated vines but not in those irrigated with drip. The absence of a location representative of L~ confounds the scheduling of drip irrigation based solely on measurements of soil moisture.

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“…In some conifer stands, three or more peaks were observed (FORD & DEANS, 1977 ;H ARRIS et (il., 1977 ;P ERSSON , 1978P ERSSON , , 1979 SUTTON, 1969SUTTON, , 1980T ROUGHTON , 1974 ;R IE -DACKER , 1976 ;R US S ELL , 1977 ;CA LDWELL , 1979 ;P ERSSON , 1983). Manipulations of the shoot, such as pruning, defoliation, and shading, affect root growth (R ICHARDSON , 1968 ;HEAD, 1973 ;PERRY, 1982 …”

Section: Fine-root Production and Turnovermentioning

confidence: 99%

“…L.Y R & H OFFMANN (1967), K OSTLER et al (1968), F AYLE (1968), S UTTON (1969, I98O), HEAD (1973), RiEnACKE R (1976), H ERMANN (1977), R USSELL (1977), C ALDWELL (1979), and PERRY (1982) nl., 1980 ;P ERSSON , 1983, Focrt., 1983. Whereas fine-root production and turnover have been compared for conifer and deciduous stands (HARRIS et al, 1977 ;M C C LAUGHERTY et at., 1982), stands of different ages (K ALE t_A, 1955 ;P ERSSON , 1978P ERSSON , , 1979G R iER ct al., 1981), and stands of different nutrient status (D YRNESS et al, 1974 ;Z OBEL el al., 1976).…”

Section: Introductionmentioning

confidence: 99%

Standing crop, production, and turnover of fine roots on dry, moderate, and wet sites of mature Douglas-fir in western Oregon

Santantonio¹,

Hermann²

1985

Ann. For. Sci.

202

115

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Shedding of Roots

Cited by 50 publications

References 55 publications

On the relationship between specific root length and the rate of root proliferation: a field study using citrus rootstocks

On the relationship between specific root length and the rate of root proliferation: a field study using citrus rootstocks

Distribution of grapevine roots and salt under drip and full-ground cover microjet irrigation systems

Standing crop, production, and turnover of fine roots on dry, moderate, and wet sites of mature Douglas-fir in western Oregon

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