NAA Treatment Research Articles

Auxin-cytokinin interaction and variations in their metabolic products in the regulation of organogenesis in two Eucomis species

In the current study, we evaluated the effect of α-naphthaleneacetic acid (NAA) individually or in combination with different cytokinins (CKs) including benzyladenine (BA), meta-topolin (mT) and isopentenyladenine (iP) on organogenesis, auxin and CK content in Eucomis autumnalis subspecies autumnalis (EA) and Eucomis zambesiaca (EZ). These species were used as model plants due to their ornamental and medicinal properties. Three leaf explants were inoculated in screw-cap jars containing 30mL Murashige and Skoog (MS) media supplemented with 5μM NAA alone or in combination with 5μM CK (BA, mT or iP). After 10 weeks (EA) or 15 weeks (EZ), parameters including shoot and root growth as well as plant fresh weight were recorded. For analysis of auxin and CK content, whole plantlets were harvested, pooled and freeze-dried for the different treatments. In both species, shoot and root proliferation as well as plant biomass were generally higher when NAA was combined with the individual CK than in NAA or CK treatment. The highest concentration of indole-3-acetic acid (IAA, 619pmolg−1 DW) and 2-oxindole-3-acetic acid (OxIAA, 2381pmolg−1 DW) were observed in EA-treated with NAA alone while mT treatment (without NAA) had the most abundant indole-3-acetyl-l-aspartic acid (IAAsp, 904 and 582pmolg−1 DW for EA and EZ, respectively) in both species. A significant concentration of total endogenous CK accumulated in both Eucomis regenerants from mT and mT+NAA when compared to the other treatments. The majority of the detected CKs were of the aromatic CK-type, mainly free bases. The potential physiological roles of these quantified phytohormones in relation to the observed morphological responses are discussed.

Effect of different stages of maturity and postharvest treatments on quality and storability of pineapple

A study was undertaken to evaluate the effects of different maturity stages and postharvest treatments on the storage behavior of Pineapple fruits. Two distinct maturity stages viz., premature (30 days before attaining optimum maturity) and optimum mature fruits were harvested and placed in the laboratory room. On the same day six postharvest treatments viz., control, preserved in unperforated polyethylene bag, tilt, 100 ppm NAA, 200 ppm NAA, and 300 ppm NAA were assigned to that fruits. The two-factor experiment was laid out in a completely randomized design with three replications. There was significant variation between two maturity stages and among different treatments in relation to fruit characteristics. At 18 days of storage, premature fruits contained the maximum shelf-life (19.33 days), total weight loss (16.00%), moisture content (92.66%), total titratable acidity (0.77%), ascorbic acid content (17.49 mg/100g fruit) while the minimum (14.5 days), (14.67%), (90.66%), (0.68%), (9.75 mg/100g fruit) in optimum mature fruits, respectively. On the other hand, optimum mature fruits had higher dry matter content (14.78%), edible portion (67.77%), TSS (16.03%), pulp to peel ratio (2.56), total sugar content (13.5%) while these were minimum (12.57%), (65.16%), (14.43%), (2.37), (10.56%) in pre mature fruits, respectively. The fruits treated with 100 ppm NAA treatment showed the highest shelf life (22.83 days), pulp to peel ratio (2.94), total titratable acidity (0.67%), ascorbic acid content (16.78 mg/100g fruit pulp) and the lowest was in total sugar content (10.96%). Fruits treated with unperforated polythene bag gave the maximum edible portion (71.72%), moisture content (88.3%), and the minimum were in weight loss (3.42%), dry matter content (11.7%), TSS (14.68%). On the other hand, fruits with 5% tilt treatment showed the minimum total titratable acidity (0.58%) and ascorbic acid content (12.28 mg/100 g fruit pulp). Fruits with control represented the highest weight loss (19.135%), dry matter content (13.7%), total sugar content (12.75%) and the lowest were in shelf life (12.66 days), edible portion (60.098%), pulp to peel ratio (1.93). Among the treated and untreated fruits, unperforated polyethylene bag and 100 ppm NAA treatment exhibited better storage performance.J. Bangladesh Agril. Univ. 12(2): 251-260, December 2014

Performance of NAA, 2iP, BAP and TDZ on Callus Multiplication, Shoots Initiation and Growth for Efficient Plant Regeneration System in Chrysanthemum (Chrysanthemum morifolium Ramat.)

Three series of plant growth regulators experiments in Chrysanthemum tissue culture, each arranged in completely randomized design (CRD), were studied to formulate efficient plant regeneration system for developing Chrysanthemum plant cell engineering. In the first experiment, 100 mg callus were cultured in liquid Murashige and Skoog (MS) medium supplemented with different combinations of NAA and BAP concentrations treatments. After 30 days of culture, heaviest callus (1.55 g) was obtained in NAA (1.0 mg L-1) + BAP (0.5 mg L-1). Consequently, shoot regeneration experiment with different kinds and concentrations of auxin, i.e. NAA and 2iP were each combined with different concentrations of cytokine BAP. Callus grown on solid MS medium supplemented with both NAA and BAP at 0.5 mg L-1 showed fastest shoot initiation (30 days), largest number of shoots (5 shoots), longest shoot length (2.88 cm). While combination of 2iP (0.5 mg L-1) and BAP (2.0 mg L-1) also produced same response on shoot initiation but shorter (1.88 cm) and only one shoot. Largest number of shoots (3 shoots) was obtained in treatment BAP (0.5 mg L-1) without 2iP, although shoot initiation was slower (39 days) with shorter length (1 cm). In a separate experiment, effect of single treatment of potential synthetic cytokine for shoot regeneration, Thidiazuron (TDZ), at different concentrations was examined. However, callus grown on TDZ incorporated medium did not produce any shoots and changed from green to brown at end of study (90 days). It was assumed that TDZ inhibited formation of shoots in Chrysanthemum callus culture.

식물생장조절물질이 산뽕나무 종자의 발아 및 유묘생장에 미치는 영향

This is the fundamental research on restoring damaged vegetation areas in the vicinity of DMZ using local native plant species. This research is aimed at identifying effective plant growth regulators (PGR) for seed germination and seedling growth of mountain mulberry, and developing effective methods for managing its germination and growth. Mountain mulberry seeds were collected from the regions in the DMZ vicinity, and tests with seven treatments using four PGRs including , kinetin, ABA and NAA, were conducted. The germination rate was calculated in two different ways of both in a growth chamber and in a greenhouse after seven days observation, and the growth characters such as leaf width/length, seedling width/length and fresh/dry weight, have been surveyed in a greenhouse for three months. Although in the growth chamber the highest germination rate was shown at a group with the kinetin treatment, it was not significantly different to that of the control group. Groups with ABA or NAA presented relatively low germination rates. As for the greenhouse test, the germination rates of all groups ranged 20~30% without significant difference each other, the reason of which might be due to low absorption by the effect of a soil drench method used in this study. The entire growth characters with the treatments of of kinetin and of were significantly different to the control. NAA treatment only showed better growth of seedling width compared to the control. Consequently, the most effective PGRs for the germination and growth of mountain mulberry near the DMZ was kinetin. Further research on examining the most effective concentration of them was needed.

Effect of Zn and NAA co-treatment on the occurrence of creasing fruit and the peel development of ‘Shatangju’ mandarin

‘Shatangju’ mandarin creasing results is serious economic loss in many ‘Shatangju’ mandarin orchards. Based on developing accurate preventive strategies for creasing fruit, the creasing of eight-year-old ‘Shatangju’ (Citrus reticulata Blanco cv. Shatangju) onto Poncirus trifoliate (L.) rootstock was investigated. It was treated twice with either Zn or Zn+NAA application in the fruit enlargement stage (18th and 27th of May, 2011), and Zn+NAA (18th and 28th of May, 2012), respectively. The Zn and Zn+NAA treatments at the fruit enlargement stage of ‘Shatangju’ significantly enhanced the levels of IAA, GA3, and tryptophan in the early peel development stage, promoted the growth and division of cells, decreased the range of peel hardness variation during fruit development, reduced creasing abnormalities in peel tissue, especially in albedo, postponed the peel thickness transition time of peel development, and significantly lowered the creasing fruit rate and cumulative abscission rate of ‘Shatangju’ mandarin. Compared with the control and Zn treatment, Zn+NAA treatment could be recommended in the fruit enlargement stage as a cultivation technique to lower the creasing fruit rate of Shatangju mandarin.

Effect of Growth Regulators (GA3 and NAA) on Growth and Development of Microplant of Potato (Solanum Tuberosum L.) Varieties Kufri Bahar and Kufri Surya

The present study was conducted at Central Research Potato Institute Campus, Modipuram, India to assess the effect of gibberellic acid (GA3) and a-naphthalene acetic acid (NAA) on in vitro microplants development in two potato varieties Kufri Bahar and Kufri Surya. The higher concentration of GA3 and NAA in combination (0.4 mg/l+0.04 mg/l) showed a decrease in parameters like number of leaves, number of nodes, internode length, shoot length and root length. The concentration of GA3+NAA (0.05mg/l+0.005 mg/l and 0.1mg/l+0.01 mg/l) led to increase in all parameters as compared to control and GA3+NAA (0.1mg/l+0.02mg/l and 0.2mg/l+0.02mg/l) treatments in both the varieties but GA3+NAA at (0.2 mg/l+0.01mg/l) concentration gave best results for number of leaves, number of nodes, internode length, shoot length and root length. Result showed that the concentration of GA3+NAA (0.05mg/l+0.005 mg/l +0.1mg/l+0.01 mg/l) is best for development of complete plantlets.

Optimizing Tuber Set and Size Distribution for Potato Seed (Solanum tuberosum L.) Expressing Varying Degrees of Apical Dominance

Plant emergence, apical dominance, tuber set, and size are affected by the physiological age of seed tubers, which can substantially impact overall crop value. This study investigated the efficacy of seed spacing (15, 25, and 35 cm) and 1-naphthaleneacetic acid (NAA) seed treatments in altering these variables in cv. Ranger Russet to improve yield and tuber size distribution of seed expressing low (2.8 stems/seed piece) and high (4.8–5.4 stems/seed piece) apical dominance. Age primed, high-stem seed produced more tubers per plant and per ha than non-aged seed; however, tuber number per ha from both seed lots fell to the same extent with decreasing plant density. Importantly, tuber set per plant increased substantially more for the physiologically older, high-stem seed as plant spacing increased. Average tuber weight also increased with decreasing plant density but the response was greatest for the physiologically younger, low-stem seed. Regardless of seed age, marketable yields were comparable at 25- and 35-cm spacing. Tuber size distributions from the 2.8-stem seed shifted from oversize (>340-g) tubers to higher percentage 113–284-g tubers as spacing decreased from 35 to 15 cm. The 5.4-stem seed produced less undersize ( 284-g tubers when planted at 35-cm spacing. Adjusting in-row spacing relative to seed age and expected stem numbers improved tuber size distribution and value. However, because plants from older seed set more tubers in response to decreasing plant density than younger seed, average tuber weight and size distribution never matched the younger seed at any spacing. Restoration of apical dominance by treatment of seed with NAA was more effective in this regard. Depending on seed age, NAA delayed plant emergence (22–74 %) and decreased stem (24–38 %) and tuber numbers per plant (8–13 %). Stem numbers from age-primed seed fell from 4.8 to 3.0 as NAA concentration increased. Marketable yields were not affected by seed age but decreased slightly (7.3 %, P 284-g) tubers, resulting in a yield profile approaching that of the non-treated younger seed. Although seed spacing and NAA treatments are effective techniques for altering tuber size distribution to maximize crop value in relation to seed age and expected stem numbers, tuber age had a small but residual effect on productivity beyond that attributable to apical dominance.

Auxin signaling is involved in iron deficiency-induced photosynthetic inhibition and shoot growth defect in rice (Oryza sativa L.)

Iron deficiency is one of the most serious nutrient limiting factors that affect rice plant growth and photosynthesis. Several phytohormones, including auxin, participate in iron uptake and homeostasis. However, how auxin signaling is involved in iron deficiency-induced inhibition of shoot growth and photosynthetic efficiency is largely unknown. The Nipponbare (NIP) seedlings displayed typical chlorotic symptoms, biomass reduction and photosynthesis depression when subjected to iron deficiency. We measured the soluble Fe content in the shoots under different conditions. The soluble Fe content in the shoots under Fe deficiency was increased by 1-naphthoxyaceticacids (1-NOA) treatment and was decreased by 1-naphthaleneacetic acid (NAA) treatment. Blocking (1-NOA treatment) or enhancement (NAA treatment) of auxin signaling also affects photosynthetic parameters under Fe deficiency conditions. Furthermore, rice microarray data (GSE17245 and GSE39429) were used to analyze the relationship between iron deficiency responses and auxin signaling in shoots. Most iron deficiency response gene expression levels in the shoots increased under exogenous auxin treatment, and most auxin early response gene expression levels responded to iron deficiency. It suggested that there is a crosstalk between iron deficiency signaling and auxin signaling. Our results indicated that iron deciencyinduced growth inhibition and photosynthesis depression were mediated by systemic auxin signaling.

Postharvest dip treatment with a natural lysophospholipid plus soy lecithin extended the shelf life of banana fruit

Lysophosphatidylethanolamine (LPE), a natural phospholipid, has been investigated for retarding senescence and promoting the shelf life of fruit and other plant tissues. LPE is a water insoluble phospholipid. For most experimental purposes, LPE is dispersed in water prior to treatment of fruit using sonication. In this study, the water solubility of LPE was improved by mixing it with soy lecithin prior to mixing with water. A combination of LPE and lecithin was used for a dip treatment of banana fruit. Banana fruit at ripening stage 2 (3/4 green) were dipped in this solution for 30min and then stored at room temperature for 10d. A combination of 200mgL−1 LPE and lecithin gave the best shelf life. In this treatment over 75% of the fruit were marketable 7d after treatment. While only about 20% and 28% of the fruit were marketable in the water (control) and lecithin treated-fruit respectively. Fruit treated with lecithin alone had better shelf life as compared to the control. Furthermore, the LPE+lecithin treatment gave better shelf life as compared to the LPE alone treatment. At 7d after dip, fruit treated with LPE+lecithin had lower ion leakage from peel tissue, higher pulp firmness, and thicker peel as compare to the control and lecithin treatments. A dip treatment with NAA (1-naphthalene acetic acid) was compared with LPE+lecithin for fruit marketability and changes in various fruit properties during ripening. Although NAA improved shelf life and retarded fruit softening as compared to the control, this treatment resulted in abnormal de-greening of fruit peel tissue. Fruit treated with LPE+lecithin had normal yellow color development and had lower ethylene production as compared to NAA and control treatments. The results of this study suggest that a dip treatment with a combination of LPE and lecithin may have potential for improving shelf life of banana fruit.

Cytokinin profiles in ex vitro acclimatized Eucomis autumnalis plants pre-treated with smoke-derived karrikinolide.

The current evidence of regulatory effect of smoke-water (SW) and karrikinolide (KAR(1)) on the concentrations of endogenous cytokinins in plants partly explain the basis for their growth stimulatory activity. Karrikinolide (KAR1) which is derived from smoke-water (SW) is involved in some physiological aspects in the life-cycle of plants. This suggests a potential influence on the endogenous pool (quantity and quality) of phytohormones such as cytokinins (CKs). In the current study, the effect of SW (1:500; 1:1000; 1:1500 v/v dilutions) and KAR1 (10(-7); 10(-8); 10(-9) M) applied during micropropagation of Eucomis autumnalis subspecies autumnalis on the ex vitro growth and CKs after 4 months post-flask duration was evaluated. The interactions of SW and KAR(1) with benzyladenine (BA), α-naphthaleneacetic acid (NAA) or BA+NAA were also assessed. Plants treated with SW (1:500) and KAR1 (10(-8) M) demonstrated superior growth in terms of the rooting, leaf and bulb sizes and fresh biomass than the control and plants treated with BA and BA+NAA. However, plant growth was generally inhibited with either SW (1:500) or KAR1 (10(-8) M) and BA when compared to BA (alone) treatment. Relative to NAA treatment, the presence of KAR(1) (10(-7) M) with NAA significantly increased the leaf area and fresh biomass. Both SW and KAR1-treated plants accumulated more total CKs, mainly isoprenoid-type than the control and NAA-treated plants. The highest CK content was also accumulated in SW (1:500) with BA+NAA treatments. Similar stimulatory effects were observed with increasing concentrations of KAR(1) and BA. The current findings establish that SW and KAR1 exert significant influence on the endogenous CK pools. However, the better growth of plants treated with SW and KAR1 treatments was not exclusively related to the endogenous CKs.

Eucalyptus dunnii Maiden plant regeneration via shoot organogenesis on a new basal medium based on the mineral composition of young stump shoots

Eucalyptus dunnii is an excellent alternative for afforestation and reforestation in frost-prone areas; however, it has limitations in the availability of propagation material. Given the great potential of tissue culture techniques for plant propagation and plant genetic transformation, the competence for in vitro organogenesis from E. dunnii cotyledons and hypocotyls was assessed. Several combinations of 6-benzylaminopurine (BAP) plus α-naphthalene acetic acid (NAA) or indole-3-acetic acid (IAA) were added (0, 0.1, 0.5, and 1 mg l−1) to a specifically developed basal medium. Moreover, the effect of the hypocotyl segments position (distal and proximal) on bud and callus regeneration was studied. Finally, microcuttings obtained from in vitro multiplication of the regenerated buds were treated with different dosages of indole-3-butyric acid (IBA) or NAA (powder based) and rooted under ex vitro conditions. Bud regeneration was observed only in hypocotyl segments, where dosages of 0.5 mg l−1 BAP plus 0.5 mg l−1 NAA or 0.5 mg l−1 IAA and distal segments resulted in higher bud regeneration rates. Histological analyses suggest that callus regeneration areas in hypocotyl explants recreate an appropriate niche for the development of pluripotent cells that give rise to buds and shoots. Either IBA or NAA treatments failed to significantly improved the ex vitro rooting of E. dunnii microcuttings, whereas >50% microcuttings rooted without application of growth regulators.

Transcriptome profiling reveals auxin suppressed anthocyanin biosynthesis in red-fleshed apple callus (Malus sieversii f. niedzwetzkyana)

Anthocyanin biosynthesis in callus culture in vitro is strongly influenced by exogenous auxin concentrations. However, the mechanisms by which auxin regulates anthocyanin biosynthesis are largely unknown. To understand the molecular basis of this phenomenon, global gene expression was analyzed in red-fleshed apple calli treated with 1-naphthaleneacetic acid (NAA; 0.3 and 10 mg/L) and 2,4-dichlorophenoxyacetic acid (2,4-D; 0.03 and 0.6 mg/L) using RNA-seq. A total of 3070 and 2533 genes were differently expressed (log2 ratio ≥ 2 at P < 0.0001) in the 2,4-D and NAA treatments, respectively. Thereof, 937 genes were up-regulated and 902 genes were both down-regulated. Genes involved in anthocyanin and flavonoid synthesis and transport into the vacuole were generally down-regulated. Higher concentrations of 2,4-D and NAA facilitated the transport of auxin and induced the expressions of genes involved in the homeostatic feedback regulatory loop. In the auxin signaling pathway, nine Aux/IAA family genes and seven ARF family genes were up-regulated. Moreover, 298 transcription factors were differentially expressed in the NAA and 2,4-D treatments. Among them, some members of MYB, bHLH, and WD40 families that directly regulate anthocyanin and flavonoid synthesis, such as MYB75 (MdMYB10), MYB12, MYB111, MYB113, TT2, and TT8 (MdbHLH3), were down-regulated by NAA and 2,4-D. Auxin also affected gene expression in other plant hormone signaling pathways, such as the cytokinin, ethylene, and gibberellic acid pathways, which also influenced anthocyanin biosynthesis. This study provides a valuable overview of transcriptome changes and gives insight into the molecular mechanism by which auxin inhibits anthocyanin biosynthesis in red-fleshed apple calli.

RAP2.6L mRNA Level in Oil Palm (Elaeis guineensis) Leaf, Inflorescence Explants and Calli Produced From Them

The RAP2.6L is a member of the ERF (ethylene response factor) subfamily β‐4 of the ERF/APETALA2 transcription factor gene family. These preliminary studies seek to investigate the mRNA level of RAP2.6L gene in oil palm (Elaeis guineensis) leaf, inflorescence explants and the calli produced from them, with a view to understanding the molecular basis of direct and indirect organogenesis. Callus was induced and proliferated from non‐chlorophyllous leaf and immature inflorescence tissues using Murashige and Skoog medium. This was supplemented with different concentrations of auxins: 2,4‐D and NAA, ranging from 100‐120 mg/l and 170‐200 mg/l respectively. The times taken for callus induction, percentage callusing explants and weight of fresh callus after 20 weeks of culture initiation were recorded. Callus production was seen to vary in time of initial response and quantity produced for both 2,4‐D and NAA treatments. The leaf tissues yielded more callus in less time than the inflorescence tissues. Treatment 100mg/l 2,4‐D was effective in producing callus in 11 % of leaf explants, while 185 mg/l NAA was more effective in producing callus in 8 % of same. The level of RAP2.6L mRNA was measured with reverse transcription polymerase chain reaction (RT‐PCR). The results obtained indicated that there was no significant difference in the RAP2.6L mRNA level among the explants and associated calli, suggesting that both explants were equally amenable to indirect organogenesis.

IAA and zeatin controls cell division and endoreduplication process in quiescent center cells of Allium cepa root

Role of endogenous IAA and zeatin level in regulation of cell division and endoreduplication processes was studied in quiescent center cells of Allium cepa using colchicine by considering morphological and cytological parameters. This resulted in formation of c-tumor at root tips, which contained endoreduplicated cells. Different concentrations of NAA and BAP (1–250 μM) were exogenously applied to these endoreduplicated root tips to depolyploidize endoreduplicated quiescent center cells. Exogenous NAA treatment showed negative response on depolyploidization of quiescent center cells of root tips. However, elongation of cells, and decrease in nucleus size was observed after exogenous NAA treatment. There was no change in length of endoreduplicated roots, and growth of root at the tip of c-tumor. Exogenous BAP showed positive response in depolyploidization of quiescent center cells of root tips. There was remarkable increase in length of roots, growth of root at tip of c-tumor and decrease in cell size and nucleus size after BAP treatment. It induced cytokinesis process in endoreduplicated meristematic cells and started cell division and differentiation process in quiescent center cells. Endogenous IAA and zeatin measured from normal, endoreduplicated and depolyploidized quiescent center root tip cells suggested that when endogenous IAA/zeatin ratio is high in meristematic cells then cell cycle shifts towards endoreduplication process but when it decreases cell cycle shifts towards cell division process.

Growth and phytochemical levels in micropropagated Eucomis autumnalis subspecies autumnalis using different gelling agents, explant source, and plant growth regulators

The therapeutic value of Eucomis species is well recognized in African traditional medicine. As a potential approach to improve growth and phytochemical content in Eucomis autumnalis subspecies autumnalis, the effect of agar (Bacteriological Agar No. 1 Oxoid) and gellan gum (GELRITE™) was evaluated using different explant sources and plant growth regulator (PGR) combinations. After 10 wk, the growth parameters were measured and phytochemical levels in 50% methanol (MeOH) extracts of the dried regenerated plantlets were determined using colorimetric methods. The highest mean shoot number (ca. 9 per explant) was observed in gellan gum-solidified media using a benzyladenine (BA) and α-naphthaleneacetic acid (NAA) treatment. Regardless of the gelling agent or PGR applied, the (initial/primary) explant source (LDL = leaf explant derived from primary leaf regenerants and LDB = leaf explant derived from primary bulb regenerants) significantly influenced all the parameters with the exception of shoot length and number of bigger shoots (≥5 mm). In most cases, the regenerants from agar-solidified media contained higher levels of flavonoids and phenolics. In terms of PGRs, the BA + NAA treatment had the highest shoot proliferation (fourfold higher than PGR-free) and number of larger shoots in LDL (gellan gum) and LDB (agar and gellan gum) regenerants. Generally, the evaluated factors (gelling agent, explant source, and PGR) significantly affected the concentrations of all the phytochemicals with the exception of total phenolic content. Taken together, the current study justifies the need to fully evaluate the manner in which in vitro culture conditions/factors affect the overall outcome of micropropagation endeavors.

Evaluation of candidate reference genes for gene expression studies in Cymbidium kanran

Quantitative real-time polymerase chain reaction (RT-qPCR) is a preferred method for rapid and reliable quantification of gene expression study. However the transcription levels of target genes may be misinterpreted due to differential expression of the reference gene which was thought to express stably. Thus, a systematic evaluation on the expression stability of nine frequently used reference genes across various tissues (including leaf, root, stem, sepal, peal, lip and gynostemium) and treatments (including phytohormone and stress treatments) in Cymbidium kanran was performed in this study. The results demonstrated that expression stability of the candidate genes varied greatly across different sample pools. Based on geNorm and NormFinder analysis, Tubulin (TUB), Actin (ACT) and Ribosomal protein S3 (RPS3) were considered to be the most suitable reference genes when all 25 samples were taken together. In addition, ACT and TUB were also the suitable internal controls in C. kanran with ABA, NaCl, cold and CuSO4 treatments. RPS3 and TUB exhibited the most stable expression pattern in NAA, 6-BA and GA treatments, while ACT and RNA polymerase beta (RpoB) could be used as the reliable internal control genes under PbAC stress. In different tissues, RPS3 and RpoB could be served as the reliable internal controls, while RpoB and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were ranked top in heat treatment. On the other hand, 18S ribosomal RNA (18S), ribosomal protein S19 (RPS19) and photosystem I P700 apoprotein B (PsaB) performed poorly in expression stability analysis across all sample pools, and they could not be used as internal controls for RT-qPCR studies in C. kanran.

Balance sheet of soil nitrogen and phosphorusvis-a-vissoybean productivity under different levels and sources of phosphorus and plant growth regulators in sub-humid Rajasthan

An experiment was conducted at Udaipur during kharif seasons of 2009 and 2010 on soybean crop involving 27 treatments i. e. three levels (20, 30 and 40 kg P2O5/ha) and three sources (single super phosphate or SSP, phosphorus rich organic manure or PROM and di-ammonium phosphate or DAP) of phosphorus in main plots and three plant growth regulators or PGRs (water spray, benzyl adenine 50 ppm and NAA 100 ppm) in sub-plots of a split plot design having three replications. Results revealed that 40 kg P2O5/ha, SSP and NAA recorded a pooled grain and stover yields of 25.95 and 37.37, 25.12 and 36.23, and 24.23 and 35.73 q/ha, respectively, which were not only maximum but also significantly superior to their respective counter treatments. Higher soybean productivity recorded in 40 kg P2O5/ha, SSP and NAA treatments linked with considerably higher mean uptake of nitrogen and P2O5 which were 243.96 and 24.79; 228.10 and 24.52 and 229.90 and 23.44 kg/ha, respectively. Data on actual soil nitrogen status after crop harvest or E values (kg/ha) showed that among different levels of phosphorus, mean N ranged from 269.52 at 20 kg P2O5 to 298.24 at 40 kg P2O5/ha, while mean P2O5 varied between 23.41 at 20 kg P2O5 and 25.99 at 40 kg P2O5/ha. Among different phosphorus sources, the order of mean E values (kg/ha) for N were PROM (294.93)>DAP (281.69)>SSP (275.98) but order for mean E P2O5 values was SSP (26.09)>PROM (24.33)>DAP (24.31). Among PGRs, the order for mean E values of N and P2O5 (kg/ha) was NAA (286.47 and 25.00)>benzyl adenine (284.64 and 24.79)>water spray (281.48 and 24.39). Data on actual mean gain or loss (G=E–initial soil nutrient status) of N showed that different levels and sources of phosphorus as well as PGRs recorded a negative balance ranging from -2.94 kg/ha at 40 kg P2O5/ha to -31.67 kg/ha at 20 kg P2O5/ha. Contrary to N, different levels and sources of phosphorus as well as PGRs recorded a positive balance in mean G values (kg/ha) that for various P2O5 levels ranged from 0.25 at 20 kg P2O5/ha to 2.83 at 40 kg P2O5/ha; for different phosphorus sources between 0.99 in DAP to 2.56 in SSP and between 1.63 in benzyl adenine to 1.84 in NAA among PGRs evaluated in this study.

Effects of different light types on root formation of Ocimum basilicum L. cuttings

Sweet basil is usually propagated by cuttings due to the ease of this method and the ability to establish mature plants quickly. However, slow root formation in this method limits early stage plant growth. To improve the efficiency of root formation, we evaluated the effects of different types of light on sweet basil cuttings. Basil cuttings were initially separated into NAA or non-NAA treatment groups to evaluate hormonal effects on rooting. Then, basil cuttings were irradiated with red, blue, fluorescent light, or natural sunlight for 16h per day. Adventitious root and shoot fresh weights as well as chlorophyll content were measured at 2, 4, and 6 weeks. Blue light was the most effective at improving root formation. Root establishment was about three times faster upon treatment with blue light than natural sunlight; root growth under blue light for 2 weeks was similar to that under natural sunlight for 6 weeks. NAA treatment of the cutting surface significantly improved root growth under blue light as compared with non-NAA treatment. The effects of NAA treatment on growth under other light types were not significantly different. However, longer exposure to blue light resulted in leaf etiolation of older leaves. Our results indicate that use of blue LEDs to irradiate basil cuttings significantly reduced the time required for both root formation and the development of conventional cuttings compared to other light types.

Exogenous auxin alleviates cadmium toxicity in Arabidopsis thaliana by stimulating synthesis of hemicellulose 1 and increasing the cadmium fixation capacity of root cell walls

Auxin is involved in not only plant physiological and developmental processes but also plant responses to abiotic stresses. In this study, cadmium (Cd2+) stress decreased the endogenous auxin level, whereas exogenous auxin (α-naphthaleneacetic acid, NAA, a permeable auxin analog) reduced shoot Cd2+ concentration and rescued Cd2+-induced chlorosis in Arabidopsis thaliana. Under Cd2+ stress conditions, NAA increased Cd2+ retention in the roots and most Cd2+ in the roots was fixed in hemicellulose 1 of the cell wall. NAA treatment did not affect pectin content and its binding capacity for Cd2+, whereas it significantly increased the content of hemicellulose 1 and the amount of Cd2+ retained in it. There were highly significant correlations between Cd2+ concentrations in the root, cell wall and hemicellulose 1 when the plants were subjected to Cd2+ or NAA+Cd2+ treatment for 1 to 7d, suggesting that the increase in hemicellulose 1 contributes greatly to the fixation of Cd2+ in the cell wall. Taken together, these results demonstrate that auxin-induced alleviation of Cd2+ toxicity in Arabidopsis is mediated through increasing hemicellulose 1 content and Cd2+ fixation in the root, thus reducing the translocation of Cd2+ from roots to shoots.

Regulation of protein turnover by heat shock proteins

The effects of different media, temperatures and plant growth regulators on the ex vitro propagation of twin-scale cuttings as well as on the relationship between starch degradation and bulblet development of Hippeastrum vittatum cv. ‘Red lion’ were studied. Sawdust was the most optimal medium for the propagation of twin-scale cuttings resulting in the lowest percentage of rotting scales and the best quality bulblets. Furthermore, 25 °C was a more suitable temperature than 30 or 20 °C. Gibberellic acid (GA3), indole-3-butyric acid (IBA) or 1-naphthyleneacetic acid (NAA) did not result in scale propagation and bulblet development. In particular, NAA treatment significantly increased the frequency of rotten scales. During bulblet formation and development, starch content in the mother scales declined earlier and more rapidly, especially in the outer scale of twin scales. The culture of scales at 30 °C resulted in a distinct increase in the consumption of starch in the scale. The starch content in bulblets increased during development. Starch accumulation in bulblets at 25 °C was most remarkable at the last stage of development. The dominant soluble sugars in the bulbs of H. vittatum were fructose, sucrose and glucose, fructose content being highest in the mother scales. However, the key soluble sugar in the bulblets was sucrose and its content increased linearly over the first 50 days.