Number Of Secondary Roots Research Articles

Synergistic effect of auxins and polyamines in hairy roots of Cichorium intybus L. during growth, coumarin production and morphogenesis

Hairy roots of Cichorium intybus obtained by infecting with different Agrobacterium rhizogenes strains (LMG-150 and A20/83) were studied for total endogenous indole-3-acetic acid (IAA) levels and indole-3-acetic acid oxidase (IAAO) activity. The roots initiated by LMG- 150 showed higher endogenous IAA levels as well as IAAO activity as compared to the roots from A20/83. Coumarin production in roots obtained by both of these strains strictly correlated with growth, with higher content in the roots obtained by LMG- 150. Moreover roots from LMG-150 showed increased growth index, length of primary roots and number of secondary and tertiary roots. The roots derived from LMG-150 were studied for total endogenous IAA and IAAO activity under the exogenous administration of polyamines and fungal elicitors. The treatment with putrescine (Put) at 1.5 mM level showed maximum endogenous IAA levels and IAAO activity as compared to the control and other polyamine administration, it also supported faster growth in terms of biomass accumulation, and total coumarin production. Of the various treatments, mycelial extract (ME) and culture media filtrate (CMF) of Pythium aphanidermatum and Phytopthora parasitica var. nicotiana, the treatment with 1 % CMF of P. parasitica var. nicotiana, resulted in maximum IAA levels and IAAO activity, which was supported by maximum biomass, coumarin production as compared to the control and other elicitor treatments. Two different regenerants of chicory obtained through A. rhizogenes LMG-150 designated as T-I and T-II, were studied for total endogenous IAA levels and IAAO activity. T-II showed higher titers of IAA with higher activity of IAAO as compared to T-I. Endogenous titer of IAA and IAAO activity was found to be maximum in transformed roots as compared to T-I, T-II, normal roots and normal plants. Our work showed a variation in endogenous auxin levels in these transformed plants. There exists a synergistic effect of endogenous IAA titers and polyamines in regulating root morphogenesis. Fungal elicitors influenced growth and coumarin production and an elicitor preparation of 1 % CMF of P. parasitica var. nicotiana gave spontaneous regeneration of shoots. The implications of these results are discussed.

Early seedling growth of pine ( Pinus densiflora ) and oaks ( Quercus serrata , Q. mongolica , Q. variabilis ) in response to light intensity and soil moisture

In climatic chambers seed germination and seedling growth of Pinus densiflora Sieb. et Zucc., Quercus serrata Thunb., Quercus mongolica Fisch. ex Turcz. and Quercus variablilis Bl. were investigated as functions of light intensity and soil moisture. In Korea these tree species occur widely and form mixed forests with different distributions. Species clearly differed in the pattern of germination and early seedling growth between light and soil treatments. The germination of pine did not differ between the experimental treatments until the breaking of the primary buds. After that, light intensity was the deciding factor for further development. In the most moist treatment (approx. field capacity) growth of the pine seedlings was strongly inhibited. For the three oak species, differences between experimental treatments first occurred after complete formation of primary leaves. Seed development strongly correlated with the weight of the acorn. The large seeded Q. variabilis (acorns with mean weight of 4.7 g) developed faster and reached larger dimensions towards the end of the experiment than Q. mongolica (2.8 g per acorn) and Q. serrata (0.9 g per acorn). Regarding height and biomass growth, the oak species showed a higher shade tolerance than pine. The proleptic shoot growth was clearly influenced by the light intensity. Root formation was favoured by a high exposure to light. In case of the oak species reduction of soil moisture increased the length of primary roots and the number of secondary roots.

Response of Sesame (Sesamum indicumL.) to Low Oxygen Concentration during Germination

Screening of crop varieties tolerant to a low oxygen environment caused by heavy rain has become an important work in monsoon Asia countries in recent years. We examined the growth of sesame (Sesamum indicumL.) germinated for 5 d in air with 0.05 02 m3 irr3 (low oxygen concentration, LO), in comparison with those germinated in air containing 0.20 Oz m3 m-3 (ambient oxygen concentration, AO). The growth of sesame was not suppressed but rather accelerated by LO. Immediately after the exposure to LO, seedlings had a 2 fold larger number of secondary roots, and more than 13.0% and 7.4% heavier in leaves and roots, respectively, over those under AO. After the oxygen treatments were over, the seedlings were immediately transferred to normal conditions to grow. One month later, the seedlings exposed to LO accelerated about two-fold dry matter (DM) over those under AO. In spite of lower content of chlorophyll, the leaf area ratio (LAR) and the net assimilation rate (NAR) of the plants exposed to LO were higher than those under AO. Compared to plants under AO, the ultimate leaf size of the cotyledon, the 1st leaf and the 2nd leaf of plants exposed to LO were 20.0, 22.9, and 27.0% greater, respectively. In comparison with pea (Pisum sativumL.), sesame respired in a different way. The total biomass yield and grain yield of plants exposed to LO were higher by 8.3% and 11.6% respectively than those under AO. These observations revealed that the hypoxic stress induced some different metabolic processes in the earlier growth stage of the plant and obviously had an advantageous effect on the subsequent growth of the plant.

Asexual propagation of Stackhousia tryonii: a step towards restoration of a rare metallophyte

Stackhousia tryonii Bailey is a rare, serpentine-endemic herb, with potential for use in phytoremediation and/or phytomining. This study evaluates the use of herbaceous heel cuttings to propagate S. tryonii on three rooting media [sand, Medium I; a commercial nursery mix, Medium II; and sand : peat moss : perlite (2 : 2 : 1; v/v), Medium III] following the application of plant growth hormones, viz. indole-3-butyric acid and naphthalene acetic acid (both as pure and commercial formulations, viz. Clonex Gel-green, Gel-purple and Gel-red), and honey. Cutting survival, rooting percentage, the number of primary and secondary roots produced, the length of the longest root and the total root length were evaluated after 10 weeks. Results show that there was a positive (P < 0.001) influence of plant growth regulator treatments on cuttings' survival. Medium III failed to support survival of cuttings. Percentage rooting (as a proportion of original number of cuttings) was 10–30% higher in Medium I than in Medium II. Cuttings treated with Clonex Gel-red, IBA at 1000 ppm and NAA at 250 ppm had 60–70% higher percentage rooting in Medium�I than in Medium II. Total number of primary roots per rooted cuttings was significantly (P�<�0.05) higher in Medium I with Clonex Gel-red and NAA at 1000 ppm. Treatments did not have significant effects on the number of secondary roots, the length of the longest root and the total root length. However, values for these parameters were significantly (P < 0.05) higher in Medium I than in Medium II. We conclude that cuttings from mature plants of S. tryonii could be used effectively to multiply S. tryonii, particularly with sand as rooting medium and prior to treatment of cuttings with Clonex Gel-red.

Variability of some morphological traits of one-year old red oak, black walnut, birch and wild pear seedlings in the nurseries of Jastrebac region

Five morphological and quantitative characteristics of one-year old seedlings of Red oak (Quercus rubra L), Black walnut (Juglans nigra L), Wild pear (Pyrus pygrowser Borkh) and Birch (Betula verrucosa Ehrh) were studied. The seedlings were produced and cultivated in the controlled conditions of the nursery in the region of Jastrebac, by the classical method. Aboveground seedling height, root collar diameter, root length, number of secondary roots and the leaf assimilation area were analysed. Intraspecific and interspecific variability of morphological features of the above species were assessed by the comparative analysis and statistical methods The comparative analysis shows the great individual variability of seedlings, which can indicate their genetic potential, adaptation to environment conditions, further spontaneous selection and the development in natural conditions. This justifies the need of the quality assessment and the first selection already in the nursery, in order to ensure the quality planting material and to reduce the risk of afforestation failure One-year old birch seedlings have the lowest average height (18.8 cm). Black walnut and Wild pear seedlings are approximately twice as high, and Red oak about 2.5 times higher. At the same time Red oak seedlings have for about one-fourth greater height than Black walnut, and for one-third greater height than Wild pear. Wild pear seedlings attain the averagely twice larger root collar diameter than Birch (2.8 cm), Red oak seedlings about 2.5 times larger diameter, and Black walnut 3.5 times larger diameter. Black walnut has a larger root collar diameter than Red oak for about one third, and almost twice larger than Wild pear. Birch, Red oak and Wild pear have almost twice longer root (1.8-1.9 times), Black walnut about 2.25 times longer. The total assimilation area of a Birch seedling is averagely 89.0 cm2. Compared to birch, wild pear has approximately double assimilation area per tree, Red oak 10 times larger, Black walnut even 14 times larger assimilation area The analysis of variance shows that the experiment is homogeneous in general, i.e. that variance within the group of the same species per all characteristics is not statistically significant at the level p>0.01. The statistically significant difference was found in the attained heights of one-year old seedlings of Red oak and Birch, as well as between them and other species, while there is no difference between Black walnut and Wild pear. All analysed species differ significantly in root collar diameter of one-year old seedlings. Black walnut and Birch differ significantly in root length, and also compared to other species. There are no statistically significant differences in root length between Red oak and Wild pear. All the analysed species differ statistically significantly per total assimilation area of one seedling .

Putrescine influences growth and production of coumarins in transformed and untransformed root cultures of witloof chicory (Cichorium intybus L. cv. Lucknow local)

The effect of putrescine on growth and production of two coumarins, esculin, and esculetin in the transformed and untransformed roots of chicory (Cichorium intybus L. cv. Lucknow local) was examined. To study the role of putrescine (Put) on growth and production of coumarins, polyamine inhibitors namely α-DL-difluromethylornithine (DFMO) and α-L-difluromethylarginine (DFMA) were used at 1 mM levels. Treatment with 1.5 mM of putrescine (Put) produced 1.96 - fold and 4.0 - fold increase in the growth of transformed and untransformed roots of chicory, respectively. The treatment with polyamine inhibitors showed much lower growth, as well as production compared with both 1.5 mM putrescine treatment and control in both transformed and untransformed chicory roots. The endogenous polyamines, both free and conjugated, were studied over the whole culture period, and it was seen that conjugated titers of all three polyamines viz., putrescine, spermidine and spermine were higher than level of free polyamines, throughout the culture period in both transformed and untransformed roots of chicory. Treatment in which polyamine inhibitors were used showed lower level of endogenous polyamines as compared with the 1.5 mM putrescine treated sample in both the systems. The treatment wherein putrescine was added at 1.5 mM level showed maximum accumulation of endogenous conjugated putrescine (2098.86±157.6 nmoles g−1 FW; 896.8±67.2 nmoles·g−1 FW), on the 14th day in both transformed and untransformed roots respectively. The production of esculin and esculetin was strictly correlated with growth in every treatment in both systems. Putrescine at 1.5 mM resulted in greater length of primary root in transformed (18.3±1.4 cm) and untransformed (6.86±0.51 cm) as compared with their respective controls (11±0.9 cm; 2.9±0.1cm) and greater number of secondary and tertiary roots. This study suggests that putrescine influences plant root development and differentiation, and it also provides insight into the morphological changes that occur in roots in response to the external supply of polyamines.

Protocolo de micropropagação da goiabeira serrana (Acca sellowiana (Berg) Burret)

Visando ao desenvolvimento de um novo protocolo para a micropropagação da goiabeira serrana (Acca sellowiana (Berg) Burret) foram estabelecidos experimentos com segmentos nodais e microestacas. As citocininas 6-Benzilaminopurina (BAP), Cinetina (Kin) e 2-Isopenteniladenina (2-iP) foram adicionadas ao meio de cultura Woody Plant Midium-WPM, visando à proliferação de brotações múltiplas dos genótipos 53B-7, 101, 529 e 152-12 x 458. As microestacas obtidas in vitro foram submetidas a diferentes períodos de indução, em 20 miM de ácido indolbutírico (AIB) e, posteriormente, transferidas para meio de cultura isento desse fitorregulador para a indução de raízes ou, alternativamente, submetidas a diferentes concentrações e tempos de exposição em AIB e transferidas para substrato. As citocininas empregadas não promoveram aumento na taxa de proliferação de brotos em relação à testemunha. O meio de cultura basal WPM, adicionado de Kin (5 miM), proporcionou maior altura média dos brotos. Segmentos nodais do acesso 101 cultivados em meio de cultura WPM, isento de fitorreguladores, apresentaram maiores taxas médias de proliferação. Pulsos de seis dias com AIB (20 miM) induziram uma maior taxa de enraizamento (68,9%), um maior número médio de raízes (1,3 raízes) e raízes com maior comprimento médio (5,6miM). Microestacas enraizadas ex vitro, pela imersão em AIB (100 miM) por 60 minutos, resultaram em maior altura das plantas (45,3mm), número de raízes secundárias (11,3 raízes), massa fresca (1069mg) e seca das raízes (282mg).

Correlation and path analysis in the F, generation of greengram (Vigna radiata (L.) Wilczek)

The correlation and path coefficients were worked out in seven parents and F, population of their 21 crosses in greengram for 13 characters. Seed yield had significant positive genotypic correlation with number of secondary roots at maturity, dry weighty of plants at maturity, plant height, clusters per plant, pods per plant, seeds per pod and hundred grain weight and harvest index. Number of pods, clusters per plant and harvest index showed high positive correlation on grain yield and also with each other. Path analysis revealed that pods per plant had the highest positive direct effect on grain yield followed by to hundred grain weight and number of seeds per pod. Plant height showed high indirect effect through number of pods, seeds per pod and hundred grain weight on grain yield. The study revealed that genetic improvement of grain yield is possible by selecting characters having high positive correlation and positive direct effect.

Enhancement of Growth and Coumarin Production in Hairy Root Cultures of Witloof Chicory (Cichorium intybus L.cv.Lucknow local) under the Influence of Fungal Elicitors.

Studies were conducted to determine the possible production of coumarins in hairy root cultures of Cichorium intybus L.cv. Lucknow local under the influence of microbial agents. Pythium aphanidermatum and Phytopthora parasitica var. nicotiana were cultured and their mycelial and medium filtrate were used for the elicitation of coumarin production. The media filtrate of P. parasitica at 1.0% v/v added to the MS basal medium led to the maximum growth of hairy roots of C. intybus, which was 1.57-fold higher than the untreated control on the 28th day of culture, along with maximum esculin and esculetin yields which were 4.06- and 3.71-fold higher than the control on the 28th day. The yields of esculin and esculetin in hairy root cultures of chicory strongly correlated with growth. To check the effect of these fungal elicitors on endogenous polyamine metabolism, titers of total endogenous polyamines were analyzed. It was confirmed that the media filtrate of P. parasitica at 1.0% v/v concentration resulted in maximum accumulation of total endogenous polyamines, wherein endogenous spermine titers were found to be maximum as compared to endogenous spermidine and putrescine titers on the 28th day. Total endogenous spermine in the case of 1.0% MF v/v P. parasitica was 1.3-fold higher than that of the control on the 28th day of culture. Maximum growth index with greater length of primary root (17.61+/-0.18 cm) and greater number of secondary and tertiary roots was recorded for the medium filtrate of P. parasitica at 1.0% v/v concentration. This study also provided an insight into the morphological changes in terms of branching patterns, occurring in roots under the influence of these fungal elicitors.

Enhancement of growth and coumarin production in hairy root cultures of witloof chicory ( Cichorium intybus L.cv.Lucknow local) under the influence of fungal elicitors

Studies were conducted to determine the possible production of coumarins in hairy root cultures of Cichorium intybus L.cv.Lucknow local under the influence of microbial agents. Pythium aphanidermatum and Phytopthora parasitica var. nicotiana were cultured and their mycelial and medium filtrate were used for the elicitation of coumarin production. The media filtrate of P. parasitica at 1.0% v/v added to the MS basal medium led to the maximum growth of hairy roots of C. intybus, which was 1.57-fold higher than the untreated control on the 28th day of culture, along with maximum esculin and esculetin yields which were 4.06- and 3.71-fold higher than the control on the 28th day. The yields of esculin and esculetin in hairy root cultures of chicory strongly correlated with growth. To check the effect of these fungal elicitors on endogenous polyamine metabolism, titers of total endogenous polyamines were analyzed. It was confirmed that the media filtrate of P. parasitica at 1.0% v/v concentration resulted in maximum accumulation of total endogenous polyamines, wherein endogenous spermine titers were found to be maximum as compared to endogenous spermidine and putrescine titers on the 28th day. Total endogenous spermine in the case of 1.0% MF v/v P. parasitica was 1.3-fold higher than that of the control on the 28th day of culture. Maximum growth index with greater length of primary root (17.61±0.18 cm) and greater number of secondary and tertiary roots was recorded for the medium filtrate of P. parasitica at 1.0% v/v concentration. This study also provided an insight into the morphological changes in terms of branching patterns, occurring in roots under the influence of these fungal elicitors.

265 Root Architecture in Quercus falcata after Physical Removal of the Radicle Tip or Copper Treatment

Quercus falcata acorns were cold-stratified for 120 days and then sown in vermiculite under greenhouse conditions. When radicles were 7 cm long, the root tip was either removed (physically pruned) or dipped in a copper hydroxide solution (copper-treated). Intact root systems were used as control. Seedlings were then moved to a root box to observe root system architectures. The box was built of clear plexiglass 2.5 mm thick, and each face was 25.7 × 35.7 cm. Styrofoam spacers were used to separate faces, and nuts and bolts were placed along edges to hold the root box together. To permit observation of the entire root system, plants were grown in a plane between the plexiglass surface and a nylon sheet that separated roots from the medium (MetroMix 510). At 7, 9, and 11 days after treatment, the entire root system was traced on an acetate sheet, and number of internal and external links and number of secondary and tertiary roots were recorded. Total length, internal and external root links length, were obtained using digital analysis (MacRhizo). Dry weight of roots and shoots was collected at the end of this experiment (day 11). Treatment effects were evident 11 days after treatment. Copper-treated plants had statistically more secondary roots and larger internal link length than control or physically pruned plants. Also, copper-treated plants had smaller mean external link length, showing a more branched root system. Root biomass was similar for all treatments; however, copper-treated plants had smaller root: shoot ratio. This suggests that copper was acting as more than a pruning agent because copper-treated plants showed a different root system architecture compared to physically pruned plants.

Comparisons of Greenhouse to Field Selection for Yield and Quality in Sweetpotato

Seedling plants from the three parents `Resisto', `Southern Delight', and `L86-33', along with three pot sizes (3.8-, 10.2-, and 17.7-cm diameters) were evaluated. Root characteristics evaluated in both the greenhouse and field included: number, length, diameter, length diameter ratio (L:D), size, skin color, flesh color, internal cambium ring (color and width), and the number of lateral and secondary roots. After greenhouse evaluation, plants were transplanted to the field. The 3.8-cm pot did not produce enough roots in the greenhouse for evaluation. In the 10.2-cm pots, greenhouse root number was correlated with the yield, root size, and L:D, and negatively correlated with skin color in the field. Flesh color was correlated with smoothness and flesh color in the field. In the 17.8-cm pots, flesh color, smoothness, and skin color in the greenhouse were correlated with the same character in the field. Skin color was also negatively correlated with smoothness in the field. No differences were found in field yield due to pot size. Results from one season showed that the 10.2-cm pot was effective for greenhouse selection of flesh color, skin color, and smoothness in seedling sweetpotato plants.

Effects of air-filled soil porosity and aeration on the initiation and growth of secondary roots of maize (Zea mays)

We studied the possibility whether the initiation of secondary roots is regulated by the air-filled porosity in soil, i.e. the availability of oxygen in the soil. Maize plants were grown in long PVC tubes (1 m long and 12 cm diameter) and were unwatered for different numbers of days so that variations of soil water content with depth were achieved on the same date with plants at the same age. The plants were harvested when their root systems were established in the whole soil column and watering had been withheld for 0, 15, 20, 25 days. A decrease of soil water content was significantly correlated with an increase of air-filled porosity in soil. The number of secondary lateral roots from segments of primary adventitious roots increased dramatically when soil water content decreased from field capacity to about 0.05 g water g-1 dried soil. The total dried mass of roots at different soil depths was also positively correlated with soil air-filled porosity. It was observed that the elongation of the initiated secondary roots responded differently to the variations of soil air-filled porosity. The length of secondary roots increased initially when the soil was dried from field capacity to 0.18 g g-1 dried soil (water potential at about−0.2 MPa, air-filled porosity 0.26 cm3 cm-3), but was drastically reduced when the soil was dried further. Obviously elongation of secondary roots was inhibited when soil water potential began to deviate substantially from an optimum value. The present results suggested that the initiation of secondary roots was greatly promoted by the increase of air-filled soil porosity, i.e. availability of oxygen. This conclusion was further verified in a separate experiment where solution-cultured maize seedlings were subjected to different aeration treatments. An obvious increase in secondary root initiation was found in plants which were aerated with normal air (21% O2) than in plants which were either not aerated or aerated with 5% O2 air. ei]Section editor: B E Clothier

Effects of air-filled soil porosity and aeration on the initiation and growth of secondary roots of maize (Zea mays)

We studied the possibility whether the initiation of secondary roots is regulated by the air-filled porosity in soil, i.e. the availability of oxygen in the soil. Maize plants were grown in long PVC tubes (1 m long and 12 cm diameter) and were unwatered for different numbers of days so that variations of soil water content with depth were achieved on the same date with plants at the same age. The plants were harvested when their root systems were established in the whole soil column and watering had been withheld for 0, 15, 20, 25 days. A decrease of soil water content was significantly correlated with an increase of air-filled porosity in soil. The number of secondary lateral roots from segments of primary adventitious roots increased dramatically when soil water content decreased from field capacity to about 0.05 g water g-1 dried soil. The total dried mass of roots at different soil depths was also positively correlated with soil air-filled porosity. It was observed that the elongation of the initiated secondary roots responded differently to the variations of soil air-filled porosity. The length of secondary roots increased initially when the soil was dried from field capacity to 0.18 g g-1 dried soil (water potential at about−0.2 MPa, air-filled porosity 0.26 cm3 cm-3), but was drastically reduced when the soil was dried further. Obviously elongation of secondary roots was inhibited when soil water potential began to deviate substantially from an optimum value. The present results suggested that the initiation of secondary roots was greatly promoted by the increase of air-filled soil porosity, i.e. availability of oxygen. This conclusion was further verified in a separate experiment where solution-cultured maize seedlings were subjected to different aeration treatments. An obvious increase in secondary root initiation was found in plants which were aerated with normal air (21% O2) than in plants which were either not aerated or aerated with 5% O2 air. ei]Section editor: B E Clothier

Cultivar Specificity of Jujube using Agrobacterium rhizogenes

Jujube (Ziziphus jujuba), is valued for its fruit, its ornamental quality, and for its use in reforestation. Jujube is considered to be very difficult to root. Five strains of Agrobacterium rhizogenes were tested on eight cultivars of jujube for the induction of roots. Strains of A. rhizogenes used were A4, TR105, AR WT, MT232, and 50. Cultivars of jujube included `Sherwood', `Sugar Cane', `So', `Li', `Silver Hill', `Tiger Tooth', `Lang', and `Contorta'. `Sugar Cane' had the lowest callus rating of the cultivars and `Li' the highest of the cultivars, followed closely by `Tiger Tooth'. `Sugar Cane' consistently had the lowest number of primary and secondary roots, and did not have any tertiary roots. `Li' consistently had the highest number of primary, secondary, and tertiary roots of the cultivars, followed by `Lang'. `Li' had more, longer roots than any of the other cultivars, followed by `Contorta'. `Li' had the best root grade rating of the cultivars. The highest percentage of rooting occurred in `Li' and `Contorta'. `Sugar Cane' had the lowest percentage of rooting. There was no significant effect of strain on any of the rooting parameters measured. Overall, `Li' rooted the best of the cultivars tested in response to Agrobacterium rhizogenes. `Sugar Cane' performed the worst.

Kemampuan berakar setek pucuk dari beberapa tanaman induk Pinus merkusii kandidat bocor getah

This study aims to examine the rooting ability of 24 clones of Pinus merkusii with high resin yield. The explants were propagated by shoot cutting that produced callus. The variables of root cuttings ability were root percentage, cutting height growth, number and length of primary roots, number and length of secondary roots, root volume, root biomass, and shoot-root ratio. The study was carried out in a Completely Randomized Design with treatments of 14 clones from hedge orchard (called as pkp clone hereafter) and 10 clones from a progeny trial (called as ppt clone hereafter) with 4 treeplots and 4 replications. The results showed that clones' origin had caused differences in root percentage, length of primary roots, number and length of secondary roots, and shoot-root ratio (P value <0.05). Clones originated from hedge orchard were always significantly better. Almost all clones from hedge orchard have a good rooted ability (>70%). Meanwhile, the clones from the progeny trial showed better height growth.

Kemampuan berakar setek pucuk dari beberapa tanaman induk Pinus merkusii kandidat bocor getah

This study aims to examine the rooting ability of 24 clones of Pinus merkusii with high resin yield. The explants were propagated by shoot cutting that produced callus. The variables of root cuttings ability were root percentage, cutting height growth, number and length of primary roots, number and length of secondary roots, root volume, root biomass, and shoot-root ratio. The study was carried out in a Completely Randomized Design with treatments of 14 clones from hedge orchard (called as pkp clone hereafter) and 10 clones from a progeny trial (called as ppt clone hereafter) with 4 treeplots and 4 replications. The results showed that clones' origin had caused differences in root percentage, length of primary roots, number and length of secondary roots, and shoot-root ratio (P value <0.05). Clones originated from hedge orchard were always significantly better. Almost all clones from hedge orchard have a good rooted ability (>70%). Meanwhile, the clones from the progeny trial showed better height growth.

Growth and Development of Young Roots of Barley ( Hordeum vulgare L.) Genotypes

Barley ( Hordeum vulgare L.) genotypes from countries with a Mediterranean climate grown in temperature-controlled glasshouse in nutrient solution to determine whether the co-ordination of root branching and growth found by other workers applied to a wider of up to 14 genotypes. There was substantial variation in the number of seminal axes produced by the genotypes, ranging from about seven for Hoshimasari and Swanneck to about four for Gerbel 'B'. The number of nodal axes was linearly related to the number of leaves and typically between one and two mainstem leaves were required before nodal axes appeared. There were small genotypic differences in the number of axes produced per leaf with values ranging from 1·5 to 2·3. The production and growth of lateral roots were coordinated so that the mean length of laterals generally increased with time. Landraces (Arabic abiad and Arabic aswad) produced more lateral roots with a faster rate extension compared with other genotypes. The length and number of primary and secondary lateral roots were related linearly, but no genotypic differences in this relation were evident. Length of primary lateral roots increased more rapidly than that of secondary lateral roots throughout the three to five leaf stage. The ratio of root weight to total plant weight decreased with time but there were only small differences within this range of genotypes.

Effect of vanadium on lettuce growth, cationic nutrition, and yield

Abstract Lettuce plants (Lactuca sativa L.) cv. ‘grandes lagos’ were cultivated in nutrient solutions containing 0 (control), 0.1, 0.2, 0.5 and 1 mg/kg of vanadium. Root and leaf growth (expressed as fresh and dry weights) was inhibited by doses 0.2 to 1 mg/kg V. Yields decreased with increasing rates of vanadium. Toxicity symptoms in the roots consisted of color darkening, club shape of the main roots, reduction of secondary root number and length, and necrosis. Leaves from plants treated with 0.5 and 1.0 mg/kg V also showed turgidity loss. Vanadium accumulated in the roots and was poorly translocated to the leaves. All the treatments significantly increased vanadium root levels, but it augmented in the leaves only at the higher doses. Vanadium affected positively foliar Ca and Fe concentrations, but it depleted ? and Mg levels of the roots. 0.1 and 0.5 mg/kg vanadium in the nutrient solution decreased Mn in the roots, whereas the highest dose raised it.

Root soluble carbohydrates of Afzelia africana Sm. seedlings and modifications of mycorrhiza establishment in response to the excision of cotyledons

Stem length, number of secondary lateral roots, shoot dry weight and reducing sugar concentrations of root were significantly reduced when translocation of reserves from cotyledons to the roots of Afzelia africana seedlings was interrupted by complete or partial cotyledon excision. The sucrose but not the glucose concentration of lateral roots also decreased significantly after complete cotyledon excision. Hartig net development rather than fungal sheath formation was affected after inoculation with the early fungal isolate E1 and by both late-stage fungal isolates L1 and L2 after partial or complete cotyledon excision. However, mycorrhizal colonization by the early fungal isolate E2 was not affected by cotyledonary reserves, suggesting that this fungal isolate has a lower carbohydrate requirement than fungal isolates E1, L1 and L2. The late-stage fungal isolates L1 and L2 induced a hypersensitivity reaction by epidermal cell walls of the host plant after complete cotyledon excision, suggesting they are more dependent than the early fungal isolate E1 on available root carbohydrate substrates for ectomycorrhizal colonization. These results are discussed in the light of the hypothesis that early and late-stage fungi were different carbohydrate requirements, and that the time sequence of colonization was related to the root carbohydrate status, which increased with time.