Total Leaf Chlorophyll Content Research Articles

Performance of promising sugarcane varieties under water stress condition

Performance of 10 promising varieties of sugarcane, viz. CoS 07250, CoS 07240, CoS 08279, CoS 08272, CoS 10239, CoS 09240, CoSe 01434, CoSe 06455, CoSe 06456 and UP 05125 was studies under water stress condition, at the research farm of UP Council of Sugarcane Research, Shahjahanapur, UP, India during spring seasons of 2012-13, 2013-14 and 2014-15. Sugarcane varieties CoS 07250 and CoSe 01434 were used as standard. Statistically pooled data of three years revealed that physiological and biochemical parameters such as transpiration rate (TR), stomatal deffusive resistance (SDR), leaf water potential (LWP) and total chlorophyll content in leaf varied significantly due to moisture stress, however, the differences were only significant in case of SDR expressing high total chlorophyll content, leaf water potential and significantly greater stomatal deffusive resistance and lower rate of transpiration under deficient moisture condition. Varieties CoS 08279, and CoS 07240 gave an indication about their drought endurance capacity. All the varieties showed significant reduction in shoot population, number of millable canes (NMC) and cane yield under deficient irrigation (two pre monsoon) as compared to normal irrigation (five irrigation pre monsoon). Varieties CoS 08279, CoS 07240 and Cose 06455 produced significantly more numbers of shoots, NMC and cane yield (63 tonnes/ha) under water stress condition along with less yield reduction percent (below 10 %), confirming thereby their drought tolerant nature. Sucrose percent in juice was not affected significantly due to water stress.

Effect of Fulvic Acid and Some Nutrient Elements on King Ruby Grapevines Growth, Yield and Chemical Properties of Berries.

The present investigation was carried out during 3 successive seasons from 2013 to 2015. The work in the first year was considered as a preliminary trial. This investigation was conducted on 16-year-old King Ruby grapevines cultivar growing at a private vineyard called Chycheny located at Meniet Samanood village near Mansoura city, Dakahlia Governorate, Egypt. The study aimed to evaluate the effect of fulvic acid and some macro-elements (Mg and K) as foliar application on vegetative growth, yield and chemical characteristics of berries.Most tested treatments gave generally a significant increase of different studied parameters, where, (Fulvic acid +Mg + K) gave the highest significant increase in bud burst and fertility (86.75 & 87.50 %) and (65.83 & 69.17 %) as compared with that of control (48.67 & 52.00 %) and (54.50 & 50.00 %) in 2014 and 2015 seasons, respectively. In addition, (Fulvic acid +Mg + K) gave a significant increase of vegetative growth such as shoot length, leaf surface area and total chlorophyll content (151.17 & 152.97 cm), (114.96 & 115.70 cm2) and (12.40 & 13.10 mg/g FW) as compared with that of control (104.70 & 107.37 cm), (94.08 & 94.37 cm2) and (7.088 & 7.207 mg/g FW) in 2014 and 2015 seasons, respectively. Also, this treatment gave a pronounced increment in yield/vine (15.29 and 15.85 kg/vine) as compared with that of control (8.36 and 8.95 kg/vine) in 2014 and 2015 seasons, respectively. Same treatments gave higher increase in the chemical characteristics of berries as SSC%, total sugars and total anthocyanin content in berry skin (20.17 & 21.00%), (18.43 & 19.20 %) and (78.98 & 79.82 mg/100g FW), while it gave the lowest decrease in acidity% (0.26 & 0.24 %) as compared with that of control (18.27 & 18.17 %), (13.83 & 14.20 %), (28.71 & 18.17 mg/100g FW) and (0.48 & 0.46 %), in 2014 and 2015 seasons, respectively.

Effect of Nitrogen Nutritional Statuses and Waterlogging Conditions on Growth Parameters, Nitrogen Use Efficiency and Chlorophyll Fluorescence in Tamarillo Seedlings

Climate change has altered rainfall patterns causing waterlogging periods that often negatively affect the performance of horticultural crops in the Andean region in Colombia. An experiment was carried out under greenhouse conditions using three-month-old tamarillo (Solanum betaceum Cav.) seedlings, which were grown under two levels of nitrogen (N) (10 and 150 mg N∙L H2O). At 28 days after transplanting (DAT), waterlogging treatments were established when well-nourished plants (150 mg N L-1 H2O) significantly showed a higher shoot length than poor-nourished plants (10 mg N L-1 H2O) (~20 cm vs. ~10 cm, respectively). Three different periods of waterlogging were performed between 35 and 37, 51 and 55, and 64 and 70 DAT by covering the holes in the plastic pots to ensure a constant water depth. Results showed that well-nourished plants without waterlogging treatments through the experiment’s stress showed a greater shoot length (30 cm), total plant dry weight (7.95 g), Fv/Fm ratio (0.62) and leaf chlorophyll content (37.51 SPAD units) than poor-nourished plants without stress condition (15 cm, 5.57 g, 0.5 and 12.69 SPAD units, respectively) at the end of the experiment. Overall, waterlogging reduced leaf area and nitrogen use efficiency (about 75% and 50%, respectively) in both N levels. However, periods of waterlogging enhanced dry matter partitioning to stems (around 30-35%) in both N levels. This study showed that tamarillo plants are susceptible to landscaping situations where periods of waterlogging can be expected regardless of their N nutritional status.

Potential of sun hemp residue to provide potato with adequate nitrogen

ABSTRACTSun hemp (Crotalaria juncea L.) residue as a proper nitrogen (N) source for a potato crop (Solanum tuberosum L.) was investigated. Leaf nutritional indices (LNI), i.e, SPAD (SPAD-502, Minolta, Japan), total chlorophyll (CHLT), and N-total content, and their validity to predict tuber yield and N recovery were estimated. Moreover, comparison with mineral N fertilization was conducted. The estimated variables exhibited linear increase patterns to sun hemp N rates. Moreover, correlation coefficients between LNI and yield components were significant. Comparison of sun hemp N-amounts with mineral nitrogen showed lower SPAD values, similar CHLT, N-total, and N recovery. However, the elevated application produced superior yields to mineral one. Sun hemp residue incorporation prior to potato accounted for adequate N supply. Additionally, LNI are appropriate tools to determine potato N status and enable yield prognoses.

Photosynthetic and antioxidative upregulation in drought-stressed sesame (Sesamum indicum L.) subjected to foliar-applied salicylic acid

Insufficient attention has been paid to the physiological responses of sesame to drought and it is unclear if exogenous plant growth regulators are beneficial to drought-stressed sesame. Thus, a field study was conducted on seven Sesamum indicum genotypes affected by two levels of irrigation (60 and 80% depletions in available soil water) and by foliar-applied salicylic acid (SA; 0 and 0.6 mM). Water deficit led to depressions in net photosynthetic rate, stomatal conductance, leaf area index, chlorophyll a, b, and total chlorophyll contents, maximum quantum efficiency of PSII, and plant dry matter and seed yield, despite increases in carotenoid concentration, superoxide dismutase, catalase, peroxidase, and ascorbate peroxidase activities. SA was found beneficial in ameliorating the depressions in all of the above characteristics, indicating that it could be applied for lessening the harmful effects of the drought stress.

Effects of Iron Sulfate, Zinc Sulfate, Iron Chelate, Powder Sulphur and Humic Acid Applications on Vegetative Growth of Sweet Cherry (Prunus avium L.)

This study was carried out in Iscehisar district of Afyonkarahisar on ‘0900-Ziraat’ sweet cherry cultivar for two successive years in 2011 and 2012. Ten different applications consisting of 80 g FeSO4.7H2O tree−1, 20 g FeEDDHA tree−1, 420 mL TKI-Humas tree−1, 80 g FeSO4.7H2O + 420 mL TKI-Humas tree−1, 200 g powder sulphur (S) tree−1, 80 g FeSO4.7H2O + 200 g powder S tree−1, 25 g ZnSO4.7H2O tree−1, 25 g ZnSO4.7H2O + 420 mL TKI-Humas tree−1 and 25 g ZnSO4.7H2O + 200 g powder S tree−1 were subjected for determination of their effect on vegetative growth of sweet cherry. In this study, shoot diameter, shoot length, leaf total chlorophyll content, leaf area and leaf iron (Fe) and zinc (Zn) contents were obtained. Shoot length, shoot diameter and leaf area showed general increases in 80 g FeSO4.7H2O + 200 g powder S tree−1 and 25 g ZnSO4.7H2O + 200 g powder S tree−1 treatments.

Effect of light regime and provenance on leaf characteristics, growth and flavonoid accumulation in Cyclocarya paliurus (Batal) Iljinskaja coppices.

BackgroundAs a highly valued and multiple function tree species, Cyclocarya paliurus is planted and managed for timber production and medical use. However, limited information is available on its genotype selection and cultivation for growth and phytochemicals. Responses of growth and secondary metabolites to light regimes and genotypes are useful information to determine suitable habitat conditions for the cultivation of medicinal plants.ResultsBoth light regime and provenance significantly affected the leaf characteristics, leaf flavonoid contents, biomass production and flavonoid accumulation per plant. Leaf thickness, length of palisade cells and chlorophyll a/b decreased significantly under shading conditions, while leaf areas and total chlorophyll content increased obviously. In the full light condition, leaf flavonoid contents showed a bimodal temporal variation pattern with the maximum observed in August and the second peak in October, while shading treatment not only reduced the leaf content of flavonoids but also delayed the peak appearing of the flavonoid contents in the leaves of C. paliurus. Strong correlations were found between leaf thickness, palisade length, monthly light intensity and measured flavonoid contents in the leaves of C. paliurus. Muchuan provenance with full light achieved the highest leaf biomass and flavonoid accumulation per plant.Conclusions Cyclocarya paliurus genotypes show diverse responses to different light regimes in leaf characteristics, biomass production and flavonoid accumulation, highlighting the opportunity for extensive selection in the leaf flavonoid production.

A nature-based approach for managing the invasive weed species Gutenbergia cordifolia for sustainable rangeland management.

BackgroundThe invasive weed species Gutenbergia cordifolia has been observed to suppress native plants and to dominate more than half of the entire crater floor (250 km2) in the Ngorongoro Conservation Area (NCA). As this species has been found to be toxic to ruminants it might strongly impact animal populations in this ecologically diverse ecosystem. Hence, a nature-based approach is urgently needed to manage its spread. We tested two Desmodium spp extracts applied to G. cordifolia and assessed the latter’s germination rate, height, fresh weight and leaf total chlorophyll content after 30 days in both laboratory and screen house experiments.ResultsSeedling germination rate was halved by Desmodium uncinatum leaf extract (DuL), particularly under higher concentrations (≥75 %) rather than lower concentrations (≤62.5 %). Likewise, in both laboratory and screen house experiments, germination rate under DuL treatments declined with increasing concentrations. Seedling height, fresh weight and leaf total chlorophyll content (Chl) were also most strongly affected by DuL treatments rather than D. uncinatum root extract, Desmodium intortum leaf extract or D. intortum root extract treatments. Generally, seedlings treated with higher DuL concentrations were half as tall, had one-third the weight and half the leaf Chl content compared to those treated with lower concentrations.ConclusionOur study shows a novel technique that can be applied where G. cordifolia may be driving native flora and fauna to local extinction. Our data further suggest that this innovative approach is both ecologically safe and effective and that D. uncinatum can be sustainably used to manage invasive plants, and thus, to improve rangeland productivity.

Evaluating fertilizer applications on spectral behaviour of rice crop using remote sensing technique

Present experiments were conducted at the research farm of Indian Agricultural Research Institute, New Delhi during Kharif 1999 and Kharif 2001 to study the influence of nitrogenous fertilizer on the tilth of rice crop by remote sensing technique. Spectral radiance observations of the crop canopy were collected with the Portable Spectroradiometer which scanned from 330 nm to 1100 nm of electromagnetic spectrum range at 5nm interval (band-width). Normalized difference vegetation index was calculated for the both tillage practices, puddle and unpuddled situation at different growth stages for different fertilizer treatment. Fertilized plots were observed to have a higher value of BR than controlled ones throughout the crop growth period, both in puddled and unpuddled treatments. The higher values of band ratio were observed in puddled rice compared to the unpuddled rice irrespective of growth stages and fertilizer application levels. Statistical correlations were developed between NDVI (Normalized difference vegetation index) and RVI (Ratio vegetation index) with LAI (Leaf area index), DM (Dry matter) production and total leaf chlorophyll content. Second order polynomial equations were developed to correlate remotely sensed data with crop biometrics. Polynomial second order equations of 'band ratio' were found to be better fitted than NDVI with crop biometrics.

Assessment of genetic diversity among okra (Abelmoschus esculentus) genotypes for quality traits

Thirty diverse genotypes of okra (Abelmoschus esculentus) were evaluated during kharif 2013 in Randomized Complete Block Design with three replications. The mature fruits (seven days after anthesis) were analysed for 19 quality traits. Dietary fibre content was recorded maximum in genotype Arka Abhay (0.09 g/g), while genotype USDO 2546 was found good source of dietary fibre (0.09 g/g) as well as protein (2.75%). Mucilage content was found maximum in genotype Punjab Padmini (6.10 %) and least mucilage was recorded in genotype DOV 26 (3.35%). Maximum iron content was recorded in genotype DOV 66 (1.71ppm) followed by DOV 27 (1.60ppm) and DOV 24 (1.53ppm). However, high calcium content was recorded in Arka Abhay and DOV 23. Genotype P 7 (13.33µg/g), DOV 2 and DOV 4 (i.e. 13.04 µg/g each) were found high in ascorbic acid. Total leaf carotenoid content was maximum in Pusa A 4 (3.35 mg/g). Total leaf chlorophyll and carotenoid content was maximum in Pusa A 4 (3.35 mg/g and 3.06 mg/g, respectively). Based on Mahalanobis D2 analysis 30 genotypes were grouped into 7 divergent clusters. Cluster VII had maximum (7) genotypes followed by cluster III and V (6 genotypes in each). Maximum inter cluster distance (6.44) was recorded between genotypes of cluster IV and VII. Cluster IV recorded maximum cluster mean for sugar (5.36%), ascorbic acid content (11.42 mg/g), ash content (1.57%), protein content (2.54%) and Mn content (0.29ppm). In principal component analysis of morphological traits, a total of 82.33% variability was contributed by 7 principal components out of 20 principal components.

Physiological responses of Pistacia vera L. versus Pistacia atlantica Desf. to water stress conditions under arid bioclimate in Tunisia

Water stress represents the major factor that affects the growth and development of plants in the arid and semi-arid areas. To improve crop management, the selection of better yielding species under such condition is a principal strategy. In this study, the responses of two pistachio species were studied after water stress followed by re-watering. Indeed, the leaf water potential, relative water content, total chlorophyll content and leaf gas exchanges were assessed during water stress and re-watering. The results showed that, under water stress, Pistacia atlantica Desf. maintained water status, leaf gas exchanges and total chlorophyll content stable compared to Pistacia vera L., which experienced a great decrease. After rehydration, P. atlantica showed fast recovery of stomatal parameters, compared to P. vera, suggesting a good tolerance to water stress. The variation of P. vera and P. atlantica responses to water stress and re-watering suggested the higher adaptation of P. atlantica to water stress compared to P. vera.

Antagonistic Streptomyces enhances defense-related responses in cotton for biocontrol of wilt caused by phytotoxin of Verticillium dahliae

Verticillium wilt of cotton is a severe soil-borne disease caused by Verticillium dahliae worldwide. Phytotoxin of V. dahliae (VD-toxin) plays a crucial role in inducing the wilt syndrome in cotton. In this study, spores of four antagonistic isolates were used in the form of powdered biocontrol agent (BCA) to protect cotton from the toxic and wilting effect of VD-toxin. The application of powdered Streptomyces BCA to soil at the time of sowing considerably enhanced defense-related enzyme activities and increased ortho-dihydric phenol and lignin contents in cotton plants after 6 week cultivation in a greenhouse. Compared to the control treatment, Streptomyces BCA treatment severely enhanced defense-related responses in cotton plants within 24 h post-VD-toxin treatment, which further decreased the accumulation of malondialdehyde and mitigated the losses of root activity, leaf total chlorophyll content, and leaf water content. Ultimately, the Streptomyces BCA treatment weakened the pathogenic effect of VD-toxin on cotton and reduced Verticillium wilt by 20.5% to 68.2% at 72 h. These results indicate that the induction of systemic disease resistance and the reduction of VD-toxin’s pathogenic effect are two important mechanisms of antagonistic Streptomyces BCA for biocontrol of Verticillium wilt of cotton.

Detection and Classification of Mosaic Virus Disease in Cassava Plants by Proximal Sensing of Photochemical Reflectance Index

Cassava Mosaic virus Disease (CMD) is the most severe and widespread virus infection that affects cassava (Manihot esculenta Crantz) crops. This paper investigates the application of photochemical reflectance index (PRI) imaging to detect and assess the impact of varying levels of CMD infection in cassava. Towards this, narrow band reflectance images of field-grown cassava plants were recorded at 531 and 571 nm by proximal sensing with a multispectral imaging system (MSIS). It was observed that the PRI values increase with increasing levels of CMD infection in all the varieties of cassava studied. A scatter plot of the PRI image intensity yielded a sensitivity of 85 % and specificity of 79 % for discriminating visibly no CMD from initial CMD and a sensitivity of 93 % and specificity of 92 % for discriminating initial CMD from advanced CMD. Area under the receiver operator characteristics (AUC-ROC) curve was used to discriminate the CMD infection level by differentiating visibly no CMD from initial CMD [AUC = 0.92] and initial CMD from advanced CMD [AUC = 0.99]. It was observed that PRI values determined from the experimental data follow a linear inverse relationship with net photosynthetic rate (Pn) (R 2 = 0.76) and total leaf chlorophyll (Chl) content (R 2 = 0.80). The results show that PRI imaging can be utilized to discriminate healthy plants from CMD and other stress infected crops by proximal sensing in outdoor plants.

Bio-hardening of in-vitro raised plants of Bhagwa pomegranate (Punica granatum)

A pot culture experiment on bio-hardening of the in-vitro raised plants of Bhagwa pomegranate (Punica granatum L.) was conducted to find out the effect of two commercially available bio-formulations containing Arbuscular Mycorrhizal Fungi (AMF) and Aspergillus niger strain AN-27. Observations on root colonization, population dynamics of microbes in rhizospheric soil, growth, physiological and biochemical parameters of biohardened plants were recorded at 180 days after inoculation. Results revealed that AMF colonization in roots of in-vitro raised pomegranate plants was found at par in plants inoculated with AMF (71.12%) and AMF + Asp (65.00%) the root colonization in these two treatments was significantly higher than Contral (10.00%). Population of Aspergillus niger in the rhizospheric soil was found significantly higher in soil inoculated with Aspergillus niger strain AN-27 (6 × 104 cfu/g of soil) as compared to non-inoculated control (2 × 104 cfu/g of soil). Significant improvement in plant height (27.0% increase), shoot fresh weight (24.8% increase), root fresh (23.3% increase) and dry weight (15.7% increase) was observed in bio-hardened plants than untreated ones. Physiological processes were also significantly improved by bio-hardening as AMF and AMF + Asp treated plants registered significantly better RWC (92.34 and 91.74 %, respectively) and photosynthesis (12.69 and 12.78 µmol CO2m-2s-1, respectively) as compared to control (87.76 % and 9.07 µmol CO2m-2s-1, respectively) and only Asp treated plants (89.99% and 9.70 µmol CO2m-2s-1, respectively). AMF inoculated and AMF + Asp treated plants registered significantly higher total leaf chlorophyll (2.97 and 3.14 mg/g fresh weight, respectively) and total phenolic content (53.00 and 52.50 mg catechol equivalent/ 100 g fresh wt., respectively) than the control and only Asp treated plants.

EFFECT OF WATER DEFICIENCY ON PHYSIOLOGICAL AND CHEMICAL PROPERTIES OF PEPPER GROWN IN GREENHOUSE

The cultivar Jalapeno pepper (Capsicum annuum var. annuum) was used in this research. The experimental design was split plot with five replications and four water restriction levels (control, 0%, 25%, 50%) were used. The research was made in a cold plastic greenhouse at Namik Kemal University, Agricultural Faculty, Department of Horticulture. After planting, plants were grown in normal growing conditions (hoeing, watering and fertilization) for a month and water restriction treatments were applied from the second month onwards. The plants development and other parameters were recorded. During the experiment leaf water potential (MPa), leaf relative water content (%), membrane damage index (%), total chlorophyll content (SPAD) and leaf temperature (°C) were measured. Artificial draught stresses made by water restrictions affected the growth and development of plants badly. The normal growth was observed in control (100% water). The plants watered with 50% were affected less than 25% and 0% water treatments. The treatment (25% water) gave noticeable stress symptoms, leaf wilting, reduced growth and development and yield reduction. The treatment (0% water) caused reduced growth, small leaf, wilting, drying, reduced yield and gradually the death of plants. As a result, leaf water potential, leaf relative water content and total chlorophyll content were the highest in 100% water treatment. The lowest leaf damage, membrane damage and leaf temperature were determined in 100% water treatment as well.

중금속(카드늄, 납, 아연)처리에 따른 자생 비비추(Hosta longipes)의 형태적 반응

The aim of this study was to examine the morphological responses of Hosta longipes, an ornamental plants for heavy metal contaminated soils in urban landscaping, to heavy metals Cd, Pb, and Zn. Plants were grown in artificial soil amended with Cd, Pb, and Zn at concentation of 0, 100, 250, and 500 mg/kg. Plant height, leaf length, leaf width, total leaf number, deaf leaf number, new leaf number, chlorophyll contents, and ornamental value were monitored from May to August. At 4 months after planting, the survival and morphological responses of H. longipes grown in soil amended with Cd at concentrations <TEX>${\geq}100mg/kg$</TEX> were severely affected compared to those grown in the control soil. Relative leaf length rate and relative leaf width rate were significantly decreased when the concentration of Pb was increased. Total leaf number, chlorophyll contents, and ornamental value were the lowest value in plants grown in soil amended with Pb at level of 500 mg/kg. Relative leaf length rate and relative leaf width rate, total leaf number, dead leaf number, new leaf number, and ornamental values had a tendency of decrease when plants were grown in soils amended with Zn. However, no significant difference was found among treatments except for plants were grown in soils amended with 500 mg/kg Zn. Therefore, Hosta longipes might be useful for phytoremediation of Zn contaminated sites as herbaceous ornamental plants.

A COMPARATIVE STUDY FOR AIR POLLUTION TOLERANCE INDEX OF SOME TERRESTRIAL PLANT SPECIES

Although water and land pollution are very dangerous, air pollution has its own peculiarities due to its transboundary dispersion of pollutants over the entire world. In any well planned urban set up, industrial pollution takes a back seat and vehicular emissions take precedence as the major cause of urban air pollution. In the present study, Air pollution tolerance index was calculated for various plant species growing at two sites Nagal village at Sahastradhara Road and the Clock Tower (the experimental site) of Dehradun city, India. The leaf samples were collected from 7 commonly present tree species. The results showed significant effects of various air pollutants on the vegetation in terms of four biochemical parameters analysed. Four physiological and biochemical parameters, which are leaf relative water content, Ascorbic acid content, total leaf chlorophyll content and leaf extract pH were used to compute the air pollution tolerance index values. Statistically significant difference was observed between control and experimental group for Ascorbic acid, t(6)=-4.848,p=.003. Paired t test for air pollution tolerance index between the two groups showed a statistically significant difference, t (6) = -4.548, p=.004. On the basis of air pollution tolerance index values for above mentioned seven tree species, Eucalyptus globus exhibited the highest degree of tolerance at all the sites followed by Ficus religiosa > Mangifera indica > Polyalthia longifolia > Phyllanthus emblica > Citrus limon > Lantana camara.

Genotype X Environment Interaction for Selected Characters from R1 Up to R5 Reproductive Stage in Soybean

Field Experiments were conducted to study the genotype x environment interaction for selected characters between anthesis and beginning of seed growth in soybean. The genotype. I.e. three parental lines and seven F8 offsprings were planted just before a wet season in two locations: at Kendalpayak-Malang and at Muneng-Probolinggo. Both locations belong to Research Institute for Legume and Tuber Crops and are located in East Java, Indonesia. The Reproductive growth stages were defined according to Fehr and Caviness. The evaluation started with begin of flowering (R1). Total leaf chlorophyll content, leaf area index, specific leaf weight, and biomass were measured at begin of seed growth (R5). Significant genotype X environment interactions were observed for all characters studied except for specific leaf weight.

Comparative growth and physiological responses of two wheat (Triticum aestivum L.) cultivars differing in salt tolerance to salinity and cyclic drought stress

Two cultivars of wheat (Triticum aestivum L.) with differential salinity tolerance were compared by evaluating the growth attributes, pigment composition and accumulation of Na+, K+, Zn2+, Fe 2+, Mn 2+ and proline. Wheat cultivars Al-Moiaya (AM) (salt tolerant) and Habbe-Druma (HD) (salt sensitive) were subjected to four levels of salinity (1.21 dS m−1, 4.4 dS m−1, 8.8 dS m−1 and 13.2 dS m−1) in factorial combinations with three drought stress (FC 30%, FC 60% and FC 90%) treatments in a randomized complete block design. Plant dry weight, leaf area ratio (LAR), soluble protein and total chlorophyll (Chl) content were higher in AM than HD. Salt-tolerant AM maintains a higher K+/ Na+ ratio and thereby is able to grow better than the salt-sensitive HD under both the stresses. The lower foliar Na+ in AM resulted in retention of higher Chl content, reflected in the strong positive correlations between plant ion status and Chl contents (Na+-Chl r2 = 0.83; Chl- Fe2+ r2 = 0.76; Zn2+ r2 = 0.93 and Mn2+ r2 = 0.88). In conclusion, our results suggested that the K+/Na+ ratio, exclusion of Na+ and ion homeostasis play much more important roles in the tolerance to salinity and drought stress than the compatible osmolyte, proline.

English

Significant increase in shoot regeneration, leaf chlorophyll content and rooting occurred when silver nitrate (AgNO3), cobalt chloride (CoCl2) or aminooxyacetic acid (AOA) were added to banana culture medium. The highest numbers of shoots per explants shoot length and leaf surface area was obtained when media were supplemented with 10 mgl-1 AgNO3. Number of shoots per explants increased three fold, shoot length and leaf surface area increased by an average of 4.5 and 2 cm2, respectively, in comparison to control. CoCl2 and AOA had less promotive effects on shoot generation with maximum shoot number per explant and shoot length achieved at 15 mgl-1. Rooting of banana shoots in vitro was enhanced by these compounds. The highest number of roots per shoot (21.7) and the longest roots (12.68 cm) were observed when rooting media was supplemented with 10 mgl-1 AgNO3. For CoCl2 and AOA the maximum rooting occurred in media supplemented with 15 mgl-1, although roots number and root length were lower than those achieved by AgNO3. Considerable increase in leaf total chlorophyll content occurred in shoots grown on media containing AgNO3 and AOA. The largest increase in leaf chlorophyll content (120%) was noted when shoots were grown in the presence of 10 mgl-1 AgNO3. This was followed by AOA which increased chlorophyll content by 35%. CoCl2 had no significant effect on leaf chlorophyll content. These findings suggest that application of ethylene inhibitors, particularly AgNO3, to culture media may be useful for improving in vitro growth performance of banana cultures. Key words: Ethylene inhibitors, banana, Musa acuminata L, in vitro culture.