Total Shoot Research Articles

Kabuli and desi chickpeas differ in their requirement for reproductive duration

There are two distinct types of chickpea (Cicer arietinum L.), called desi and kabuli, that differ in size, color and surface of seeds, flower color and morphology. Both these types are divergent geographically and broadly vary in their adaptation, nutrition, biotic and abiotic stress tolerance. In a field evaluation of large number of well-adapted F4 progenies of both desi and kabuli had shown that the grain yields were lower in all the kabulis as a consequence of lesser total shoot biomass production and lesser harvest index. The vegetative duration of kabulis was shorter and the reproductive duration extensively longer explaining why the shoot biomass productivity is low. In another field trial with a subset of the minicore chickpea germplasm, the canopy temperature depression of the kabulis were observed to be relatively lower with a low variation among the accessions and also the grain yields were lower explaining the poor adaptation of kabulis to terminal drought under Patancheru. The anatomy of roots had shown that there were quick loss of cortical layers and the presence of greater number of wider xylem vessels in kabulis relative to desis and that the kabulis were equipped to use more water with less resistance to water flow. More desi×kabuli introgressions are suggested for improving the adaptability and yield stability of kabulis under peninsular Indian environments.

EFFECTS OF SALINITY AND CALCIUM ON THE GROWTH AND CHEMICAL COMPOSITION OF PISTACHIO SEEDLINGS

Poor quality of irrigation water (high salinity) has reduced the yields of pistachio over recent years, especially in Kerman. The effects of four salinity levels [0, 30, 60, and 90 mM sodium chloride (NaCl)] and three calcium (Ca) levels [0, 0.5, and 1 mM Ca as calcium nitrate (Ca(NO3)2.4H2O)] on growth and chemical composition of pistachio seedlings cv. ‘Badami’ were studied in sand culture under greenhouse conditions in completely randomized design (CRD) with four replications. After 170 days, leaf area, leaf number, shoot and root dry weights were determined. Also shoot and root sodium (Na), potassium (K), Ca, and magnesium (Mg) concentrations were measured. Results showed salinity decreased all growth parameters. Ca application increased shoot and root Ca concentrations and root K concentration, while Ca application decreased shoot K concentration and shoot and root Mg concentrations. Salinity decreased shoot Ca, root K, and root Mg concentrations, while salinity increased shoot and root total sodium uptake, and shoot and root Cl concentrations.

Effects of elevated copper levels on biological nitrogen fixation and occurrence of rhizobia in a Tanzanian coffee-cropped soil

A study was conducted to investigate the effects of increasing copper concentration in soil on rhizobial occurrence and the process of biological nitrogen fixation. Two slow-growing bradyrhizobial strains CP1 and GM8 and two fast-growing rhizobial strains PV1 and PV2 were studied by comparing their performance under increasing copper concentrations in greenhouse-based assays involving modified Leonard jar assemblies and potted-soil experiments. Additionally, field samples from soils grown to coffee and subjected to long-term use of copper-based fungicides were analyzed for their total indigenous rhizobial populations using the most probable number-plant infection technique. Results indicated that elevated copper levels in the growth medium had inhibitory effects on nodulation, biological N2 fixation and overall rhizobial numbers in soil. Significant (p= 0.05%) reductions in fresh nodule mass, fresh nodule volume and total shoot nitrogen were recorded when copper concentration was increased from 0 to 100 ppm in both modified Leonard jar assemblies and potted-soil trials. Effective decrements in all the three parameters of fresh nodule mass, fresh nodule volume and total shoot nitrogen were more pronounced with the slow-growing bradyrhizobial strains of CP1 and GM8 than with the fast-growing PV1 and PV2. The MPN-plant infection technique results showed a non-significant (p=0.05) but substantial decrement in rhizobial and bradyrhizobial numbers when the copper-contaminated field soil (82.5 mgCu/g soil) was compared to a control soil (1.8 mgCu/g soil). The study concludes, therefore, that elevated levels of copper in soil could be harmful to free-living rhizobia and their abilities to fix N2 in respective symbiotic associations with legume species. Such negative effects were more pronounced in the slow-growing bradyrhizobial than rhizobial species used.

Arbuscular mycorrhizal effects on plant water relations and soil greenhouse gas emissions under changing moisture regimes

Increased nutrient and/or water uptake by AM symbiosis may affect soil biochemical properties and greenhouse gas (GHG) emissions. A greenhouse experiment was carried out to compare mycorrhizal tomato (76R MYC) and its non-mycorrhizal mutant (rmc) on the CO2 and N2O emissions from an organically-managed soil. Plants were grown for 10 weeks in pots with compost amended soil and subjected to two consecutive dry down cycles to simulate changing moisture regimes in the field. Dry downs were applied gradually through controlled watering treatments. The effects of AM and soil moisture in GHG emissions were assessed in root in-growth PVC cylinders installed in the pots. Gas samples were taken from the cylinders using static chambers 4 h after each watering event. Photosynthetic rates and stomatal conductance of the plants were assessed after watering using a field portable open flow infra-red gas analyzer. Soil moisture was monitored throughout the experiment. Plant biomass and total shoot N, P and K as well as soil content of DON, DOC, NH4+–N, NO3−–N and microbial biomass C, were assessed at harvest. For the same shoot growth and nutrient content, rmc plants allocated more resources to root biomass than mycorrhizal plants. AM symbiosis improved the capacity of the plants to adapt to changing soil moisture, increasing photosynthetic rates and stomatal conductance at high soil moisture but decreasing them when soil moisture was lower. In addition AM symbiosis helped to regulate N2O emissions at high soil moisture. Control over N2O emissions by AM plants seemed to be driven by a higher use of soil water and not by increased N uptake.

Effect of root pruning and irrigation regimes on pear tree: growth, yield and yield components

The effect of root pruning (RP) as compared with non-root pruning (NP) and the potential of supplemental irrigation in alleviating the negative effect of root pruning on fruit growth, yield and yield components were investigated in a pear orchard from 2010 to 2011. Results showed that the total shoot length and the number of shoots per tree decreased by 72% and 43%, respectively, in the RP compared to the NP trees; however lateral root growth was stimulated by the RP treatment in the upper soil layers (30–40 cm). Full irrigation and deficit irrigation treatments stabilized the return bloom and improved fruit yield and size compared with the non-irrigated treatment without stimulating vegetative growth. Conclusively, the results indicate that root pruning is an effective practice controlling excessive shoot growth, and supplemental irrigation can improve fruit yield and quality in the root pruned trees. Therefore, a combination of root pruning and irrigation could be a promising alternative to control tree size and secure a stable fruit yield in pear orchards.  

Design of tissue culture media for efficient Prunus rootstock micropropagation using artificial intelligence models

Establishing optimized protocols for micropropagation of some economical plants, such as Prunus sp., is still one of the most important challenges for in vitro plant culture researchers. As an example, micropropagation of GF677 hybrid rootstocks (peach × almond) are extremely dependent on the medium ingredients and a large undesirable proportion of GF677 shoots need to be discarded as a result of hyperhydricity and chlorosis. In this study, an artificial intelligence technique—specifically neurofuzzy logic—has been employed, as a modeling tool, to increase knowledge on the effect of 8 ion macronutrients (NH4 +, NO3 −, Ca2+, K+, Mg2+, SO4 2−, PO4 2− and Na+; as inputs) on three growth parameters (outputs): total number of shoots per explant, healthy number of shoots per explant, and their bud number. The model delivered new insights, by three sets of IF–THEN rules, pinpointing the key role of NO3 − and their interactions (NO3 − × Ca2+ and NO3 − × Ca2+ × K+) on all growth parameters measured. All growth parameters showed a high correlation ratio between experimental and predicted values being 77.48, 91.78 and 90.78 for total shoots, healthy number and bud number, respectively. Regression coefficients higher than 77 % together with statistical significant ANOVA (p < 0.01) indicated good performance of neurofuzzy logic models. Moreover, The model also can be used for inferring the best combination of ion concentrations to obtain high quality GF677 micropropagated shoots. In conclusion, we assess the utility of neurofuzzy logic technology in modeling complex databases, identifying new complex interactions among macronutrients, and inferring new results and valuable knowledge, which can be applied to design new plant tissue culture media and improve plant micropropagation.

Investigation the quality and quantity of Melissa officinalis L. under chemical and bio-fertilizers of sulfur

In order to investigate the effect of chemical and bio-fertilizers of sulfur on yield and morphological traits of Melissa officinalis, this project was conducted in Research Institute of Forests and Rangelands, Karaj, Iran in 2012. The experiment was conducted as factorial experiment in the form of a randomized complete block design with three replications in filed condition. The main factor was sulfur solubilizing bacteria (Thiobacillus thioparus) in two levels: inoculation and lack of inoculation. The sub factor was sulfur fertilizer of bentonite source in two levels (0 and 500kg/ha). The analysis of variance showed that the effect of Thiobacillus thioparus was different for plant height, sub stem number and leaves yield (α≤0.05) and for tillers number, sub-sub stem number, yield of total shoot and stem yield (α≤0.01), while the effect of sulfur fertilizer was different only for tillers number (α≤0.01). Effect of chemical and bio-fertilizers were not significant for any of the traits. The comparison showed that bio-fertilizers application had the highest increase in measured traits. So that the highest plant height (35.55cm), sub stem number (34n/p), sub-sub stem number (230n/p), yield of total shoot (604.68kg/ha), leaf yield (429.73kf/ha) and stem yield (174.94kg/ha) belonged to it, Also the highest tiller number observed in chemical fertilizer application. Overall the results indicated that Thiobacillus thioparus application significantly increased shoot yield than sulfur chemical fertilizer and suggested micro organisms efficiency and need to pay more attention to them in agricultural systems.

Parâmetros genéticos e análise de trilha para o florescimento precoce e características agronômicas da alface

O objetivo deste trabalho foi avaliar os parâmetros genéticos das características agronômicas e de tolerância ao florescimento precoce de onze cultivares de alface, bem como verificar a existência de associação entre as características. O experimento foi realizado em ambiente protegido, em delineamento de blocos ao acaso, com quatro repetições e doze plantas por parcela. Quarenta e cinco dias após o transplantio das mudas, foram mensuradas as seguintes características: massa de matéria fresca total e "comercial" da parte aérea, massa de matéria seca "comercial" da parte aérea, massa de matéria fresca e seca da raiz, diâmetro e circunferência da cabeça, altura de planta, número de folhas por planta e número de dias até a antese. Há variabilidade genética entre as cultivares, em todas as variáveis, exceto quanto à circunferência de planta e matéria fresca da raiz. As cultivares Regina 500, Lívia e Atração foram superiores quanto ao número de dias para o florescimento e também para as demais características avaliadas. A seleção contra o florescimento precoce ocasionou ganho em todas as características; porém, não interferiu na matéria seca da raiz. A matéria fresca da parte aérea e o diâmetro de cabeça são indicadas para a seleção indireta contra o florescimento precoce.

Stem Cutting Propagation in Whole Pine Tree Substrates

Wood-based substrates have been extensively evaluated for greenhouse and nursery crop production, yet these substrates have not been evaluated for propagation. The objective of this study was to evaluate processed whole loblolly pine trees (WPT) (Pinus taeda) as a rooting substrate for stem cutting propagation of a range of ornamental crops. Substrates included processed WPT, pine (Pinus sp.) bark (PB), and each mixed with equal parts (by volume) peatmoss (PM) (WPT:PM and PB:PM, respectively). Substrate physical (air space, container capacity, total porosity, bulk density, and particle size distribution) and chemical [pH and electrical conductivity (EC)] properties were determined for all substrates. Rooting percentage, total root length, total root volume, and total shoot length were evaluated for four species in 2008 and five species in 2009. Substrate air space was similar between PB and WPT in the 2008 experiment, and likewise between PB:PM and WPT:PM. In the 2009 experiment, PB and WPT had similar substrate air space. The addition of PM to PB and WPT resulted in reduced air space and increased container capacity in both experiments. The proportion of fine particles doubled for PB:PM and WPT:PM compared with PB and WPT, respectively. Substrate pH for all substrates ranged from 6.0 to 6.9 at 7 days after sticking (DAS) cuttings and 6.9 to 7.1 at 79 DAS. Substrate EC was below the acceptable range for all substrates except at 7 DAS. Rooting percentage was similar among substrates within each species in both experiments. The addition of PM resulted in significantly greater total root length for PB:PM and WPT:PM compared with PB and WPT, respectively, for five of the eight species. Shoot growth was most vigorous for PB:PM compared with the other substrates for all species. The study demonstrated a range of plant species can be propagated from stem cuttings in whole pine tree substrates alone or combined with PM.

MORPHOLOGICAL AND PHYSIOLOGICAL RESPONSES OF SOME OLIVE CULTIVARS SEEDLINGTO DIFFERENT CALCIUM CARBONATE LEVELS AND DROUGHT IN SOIL.

The Morphological and physiological responses of 6 olive cultivarsseedlings namely; “Agezee”, “Koroneiki”, “Picual”, “Nebal”,“Manzanillo” and “Coratina” to three levels of calcium carbonate in soil(9.4%, 22% and 38.1% CaCO3) and two irrigation levels which were 60%and 30% available water “A.W” were studied during two successiveseasons, 2012 and 2013.The present study was achieved on one-year oldseedlings grown in black plastic bags under saran green house conditionsat the experimental farm of the Fac. of Agric. at Demo, Fayoum, Egypt.A negative relationship was found between CaCO3% in soil and/ordeficit irrigation on growth Parameters of seedlings (plant height, leafarea, total shoot length/plant, dry weight/plant, root length density), totalchlorophyll (mg/g fresh weight) and total carbohydrate %.There were great differences among cultivars in their response toCaCO3% in soil and drought. The cvs. that were most tolerant are“Nebal” followed by “Agezee” but “Coratina”, “Koroneiki” and“Manzanillo” were most susceptible; while “Picual” was intermediatetolerant. 53

Examination of Cold Deacclimation Sensitivity of Annual Bluegrass and Creeping Bentgrass

ABSTRACTAnnual bluegrass (Poa annua L.) (AB) frequently exhibits increased susceptibility to winter injury compared to other cool‐season turfgrass species such as creeping bentgrass (Agrostis stolonifera L.) (CB). Interspecific differences in winter survival of these two species may be associated with enhanced sensitivity of AB to decreases in freezing tolerance (deacclimation) during winter and early spring months; however, there is limited understanding of the factors associated with cold deacclimation between these two species. Therefore, the objective of this research was to determine the deacclimation sensitivity of one AB ecotype and one CB cultivar in response to varying temperature increases and durations. Total shoot growth and freezing tolerance (lethal temperature resulting in 50% mortality [LT50]) of AB and CB was monitored throughout cold acclimation (20, 2, and –2°C) and following exposure to a combination of 4, 8, or 12°C for 1 or 5 d. Overall, freezing tolerance of AB (LT50 of –17.7°C) was significantly lower than CB (LT50 of –21.2°C) following cold acclimation, and in general CB maintained higher levels of freezing tolerance throughout deacclimation compared to AB (LT50 of –16.2 and –12°C, respectively). Both AB and CB exhibited deacclimation in response to above‐freezing temperatures; however, the threshold temperature required to induce greater losses in freezing tolerance was lower for AB compared to CB. Specifically, a 2.5‐fold greater loss in freezing tolerance was detected in AB compared to CB following exposure to 4°C. Furthermore, total shoot growth and LT50 were correlated during deacclimation in these species.

SPAD Values and Nitrogen Nutrition Index for the Evaluation of Rice Nitrogen Status

Plant-based diagnosis is one of the most important methods to determine nitrogen (N) content of crops. Our objective was to establish the relationship between soil-plant analysis development (SPAD) values and N nutrition index (NNI) during the three developmental stages of rice and apply the SPAD meter as diagnostic tools for predicting grain yield response to N fertilization. We determined the SPAD values of four uppermost fully expanded leaves of two rice cultivars at six N fertilization levels at three growth stages and examined the relationship between SPAD values and NNI. The critical N concentration (Nc) was 5.31 W–0.5 in Xiushui63, and 5.38 W–0.49 in Hang43, where W is the total shoot biomass. The correlation between SPAD value and NNI varied with the leaf position, developmental stage, and variety. The lower leaf appeared to be more sensitive to the N level than the upper leaf in the response of biomass, and could be more suitable as a test sample for N status diagnosis, especially in the booting and heading stage. The dependence of grain yield on SPAD values of the fourth fully expanded leaf (L4) was significant at booting stage (R2L4 = 0.82** in 2011, R2L4 = 0.72** in 2012). Ratio of SPAD values of L4 to that in the N-saturated plot (RSPAD) (R2L4 = 0.92** in 2011, R2L4 = 0.77** in 2012) and NNI (R2 = 0.96** in 2011, R2 = 0.86** in 2012) at booting stage demonstrated a closer relationship with grain yield.

여름 질소 시비량에 따른 '부유' 감나무의 생장과 노화 중 잎의 양분 변화

With pot-grown 4-year-old 'Fuyu' persimmon trees, this study evaluated the effect of different nitrogen (N) rates during summer on fruit characteristics, changes of leaf nutrients after harvest, reserve accumulation, and early growth the following year. A total of 0, 36 g N in June, and 72 g N in June and July was fertigated to each tree using urea solution. All the fruits were harvested on Nov. 3. Although not significant, fruits were larger for the 36 g and 72 g N than the 0 g N. Fruits for the 0 g N, having lower N concentration, were softer and had a better coloration and higher soluble solids, indicating that they matured earlier. SPAD value on Nov. 3 was 19.2 for the 0 g N and 54.9 for the 72 g N, and then the values linearly decreased in all the treatments by Nov. 14, exhibiting rapid leaf senescence. Specific leaf weight, being the lowest for the 0 g N, also gradually decreased during this period. Increasing N level significantly increased cross-sectional area of the trunk. Leaf N concentration on Nov. 3 was 0.87% for the 0 g N, whereas it was 1.18 and 1.52% for the 36 g and 72 g N, respectively. The N fertigation tended to increase leaf concentrations of soluble sugars, starch, and amino acids. Contents of N, P, K, soluble sugars, starch, and amino acids per unit leaf area gradually decreased in all the treatments during the 11 days after harvest, and the extent of the decrease was the lowest for the 0 g N. On the other hand, those of Ca, Mg, and protein did not consistently change during this period. The N fertigation resulted in higher concentrations of N in dormant shoots on Nov. 14, and although not great, it also increased soluble sugars, starch, amino acids, and protein. Clear differences were found in number of flower buds per one-year-old branch and total shoot length per tree the following year. The 72 g N trees had 5.6-fold more flower buds and 1.9-fold more shoot length, compared with those of 0 g N trees. However, it was noted that tree growth the following year was not significantly different between the 36 g and 72 g N the previous year. It was concluded that N rate during summer should be adjusted with considering the changes of fruit maturation, mobilization of leaf nutrients, and reserve accumulation.

CO2및 기온 상승이 '후지'/M.9 사과나무의 광합성, 신초생장 및 과실품질에 미치는 영향

This study was conducted to find out the influence of elevated atmospheric CO2 concentrations and air temperature on photosynthesis and fruit quality of ‘Fuji’/M.9 apple trees and to investigate these to the effects of climate change during the last four years (2009-2012). The treatments employed were: ‘Ambient’ (ambient temperature + ambient CO2 concentration); ‘High CO2’ (ambient temperature + elevated CO2 concentration); ‘High Temp.’ (elevated temperature + ambient CO2 concentration); and ‘High CO2 + High Temp.’ (elevated temperature + elevated CO2 concentration). The elevated temperature plots were maintained at 4 o C higher than ambient air temperature, while the elevated CO2 plots were maintained at 700 µmol·mol �1 . Annual treatment period was applied from end of April to beginning of November for four years. Results showed that elevated CO2 decreased stomatal conductance and leaf SPAD value, but increased photosynthetic rate, intercellular CO2 concentration (Ci), and starch content of mesophyll tissue. In the vegetative growth, elevated temperature increased total number of shoot and total shoot growth per tree, but elevated CO2 decreased average shoot length. In the fruit quality, elevated CO2 increased soluble solid content, fruit red color, and ethylene production. In conclusion, elevated CO2 increased photosynthetic rate of apples during the early growth, but effect of increased photosynthetic rate due to elevated CO2 was decreased during latter growth stage. Elevated temperature, on the other hand, tended to decrease photosynthetic rate of apples during the early growth, but that tended to increase during latter growth stage. Both elevated CO2 and temperature tended to decrease the degree of decreased photosynthetic rate due to each factor.

Alleviation of nickel toxicity in wheat (Triticum aestivum L.) seedlings by selenium supplementation

Abstract Hydroponically grown wheat seedlings were treated with 50 μM N i and/or 15 μM Se. After a 7-day culture period, their growth parameters, N i, Se, F e, and M g contents, electrolyte leakage, photosynthetic pigment concentrations, and photochemical activity of photosystem II were determined. Exposure of wheat seedlings to N i alone resulted in reduction in the total shoot and root lengths, by 22% and 50%, respectively. Addition of Se to the N i-containing medium significantly improved the growth of these organs, compared to the seedlings subjected to N i alone. Application of Se decreased the accumulation of N i in shoots and roots and partially alleviated the N i-induced decrease in F e and M g concentations in shoots. Electrolyte leakage increased in response to N i stress, but in shoots it was diminished by Se supplementation. Exposure to N i led to a decrease in chlorophyll a and b contents and enhancement of chlorophyll a/b ratio, but did not influence the concentration of carotenoids. Enrichment of the N i-containing medium with Se significantly increased chlorophyll b content, compared to the seedlings treated with N i alone. Photochemical activity, estimated in terms of the maximum quantum yield of photosystem II , decreased in response to N i treatment but was significantly improved by simultaneous addition of Se. Results of our study suggest that alleviation of N i toxicity in wheat seedlings by Se supplementation may be related to limitation of N i uptake.

Effect of Pseudomonas luteola on mobilization of phosphorus and growth of young apple trees (Ligol)—Pot experiment

The use of phosphate solubilizing bacteria as inoculants may increase the concentration of plant-available phosphorus in soil. Among soil microorganisms, bacteria from the genus Pseudomonas have received considerable attention as plant growth promoters. A phosphate solubilizing bacterium isolated from non-rhizosphere soil collected in Central Poland, was identified as Pseudomonas luteola BN0834 on the basis of biochemical methods and 16SrDNA sequence analysis. P. luteola strain BN08-34 was tested for: solubilization of inorganic and organic compounds of phosphorus (calcium phosphate, zinc phosphate, hydroxyapatite and calcium phytate); indole acetic acid (IAA), siderophore production and biosurfactant production; and the ability to grow on a medium without nitrogen added. Young apple trees, cultivar Ligol (rootstock M26), were grown in a pot-house for 14 weeks in pots filled with nonsterilized soil, classified as a sandy loam. The P. luteola BN0834 was introduced into the soil in a number equal to the number of native phosphate solubilizing microorganisms (PSM) (P. luteola) in soil or in a number ten times higher than the number of native PSM in soil (P. luteola×10). Shoot numbers; average and total shoot lengths; contents of P, K, Mg and Ca in plant material; contents of available P, K and total Mg in non-rhizosphere soil, changes in the number of cfu (colony forming units) of microorganisms (PSM, cophiotrophs, oligotrophs and fungi) in non-rhizosphere soil and in the rhizosphere of the apple trees were studied. When the higher number of P. luteola BN0834 was introduced into soil without a mineral fertilizer added near the surface of the roots, positive correlations were found between the number of PSM in the apple tree rhizosphere and the content of available P in non-rhizosphere soil and also between the number of PSM in the apple tree rhizosphere and the amount of P, K and Ca in plant leaves. The highest total shoot length was also obtained from P. luteola×10 application.

Effect of Poultry Manure and Irrigation Depth on the Growth of Fluted Pumpkin (&lt;em&gt;Telfairia occidentalis&lt;/em&gt; Hook. F) During the Dry Season in the Niger Delta Region of Nigeria

Farmers in the Niger Delta region of Nigeria only practice rainfed agriculture, partly because of the misconception that the area has abundant rainfall even though the region has distinct wet and dry seasons. This, coupled with the low soil fertility always results in crops being produced at the subsistence level. This experiment was therefore conducted during the dry season to investigate the growth response of fluted pumpkin (Telfairia occidentalis Hook. F) to different combinations of poultry manure and depths of irrigation in a loamy sand soil. It was a randomized complete block design experiment involving three levels each of poultry manure and irrigation with three replications. The treatments comprised random combinations of 10, 20 and 30 t/ha poultry manure with 3, 4 and 5 mm depths of irrigation, including control treatment that had neither manure nor irrigation. Results indicated that the application of poultry manure and irrigation produced significantly higher values of all the growth parameters than the control. Although the combination of 30 t/ha manure and 4 mm depth of irrigation produced the maximum leaf area, the best result in terms of vine length, number of leaves, vine fresh weight and total shoot yield was obtained by combining 30 t/ha manure with 3 mm irrigation depth. This study therefore recommends the application of 30 t/ha poultry manure and 3 mm depth of irrigation for the cultivation of fluted pumpkin during the dry season in the Niger Delta region of Nigeria.

Inisiasi Tunas Ganda Tanaman Manggis Malinau melalui Kultur In Vitro untuk Perbanyakan Klonal

Mangosteen (Garcinia mangostana L.) is one of the most promising tropical fruits for export. The major constraint to increase fruit production of the spesies is the long juvenile period. Seedless, sweet and juicy variety of mangosteen had been found in Malinau. In vitro propagation technique offers possibility to produce sufficient number of seedlings any time. This research was aimed at obtaining the appropriate media formula to enhance shoot proliferation. This research consisted of shoot induction and multiplication and shoot elongation. The materials were the fresh mangosteen seeds from the Malinau mangosteen trees. The explant used in the trial was seeds which were divided into four slices. The use of 8 to 16 mg BA L-1 combined with 0.2 mg thidiazuron L-1 resulted in the best shoot induction of 52 shoot buds per explant at the 6th week after planting with the mean height of 0.3 cm. Upon subculturing in to the similar media, the number of shoot tends to increase. For multiplication, low concentration of BA (2 to 4 mg L-1) and thidiazuron 0.05 mg L-1 were applied to increase the numbers of shoots. The total shoot number obtained in the media with 0.05 thidiazuron without BA was 11.25 and in the media with 2 mg BA L-1 + 0.05 mg thidiazuron L-1 was 8.7 shoot explant-1. The result showed that the best media for shoot elongation was MS + 1 mg BA L-1 + 2 mg kinetin L-1. The length of the shoots were in the range of 0.5-0.8 cm. Keywords: BA, Garcinia mangostana, in vitro culture, shoot multiplication, thidiazuron

Prosperity of Douglas fir (Pseudotsuga menziesii [Mirb.] Franco) plantations in relation to the shelter

The study evaluates the mortality, growth and qualitative characteristics of Douglas fir transplants planted out on clear-cut areas with different shelter. We assessed 11 clearings situated in the Forest Site Complex 4K &amp;ndash; acidic beech (Fagetum acidophilum). The young trees were assessed 3 years after planting for the following parameters: total shoot length, increment, root collar diameter, number of multiple stems, stem curvature, crown form, length of needles, colour of needles and frost damage. The lowest mortality and the best growth of Douglas fir plants were recorded in small, sheltered gaps. Large, unsheltered gaps showed low survival, slower growth and poor vitality of plants. &amp;nbsp;

Rapid shoot‐to‐root signalling regulates root hydraulic conductance via aquaporins

We investigated how root hydraulic conductance (normalized to root dry weight, Lo ) is regulated by the shoot. Shoot topping (about 30% reduction in leaf area) reduced Lo of grapevine (Vitis vinifera L.), soybean (Glycine max L.) and maize (Zea mays L.) by 50 to 60%. More detailed investigations with soybean and grapevine showed that the reduction in Lo was not correlated with the reduction in leaf area, and shading or cutting single leaves had a similar effect. Percentage reduction in Lo was largest when initial Lo was high in soybean. Inhibition of Lo by weak acid (low pH) was smaller after shoot damage or leaf shading. The half time of reduction in Lo was approximately 5 min after total shoot decapitation. These characteristics indicate involvement of aquaporins. We excluded phloem-borne signals and auxin-mediated signals. Xylem-mediated hydraulic signals are possible since turgor rapidly decreased within root cortex cells after shoot topping. There was a significant reduction in the expression of several aquaporins in the plasma membrane intrinsic protein (PIP) family of both grapevine and soybean. In soybean, there was a five- to 10-fold reduction in GmPIP1;6 expression over 0.5-1 h which was sustained over the period of reduced Lo .