Tolerant Category Research Articles

Evaluation of air pollution tolerance index of tree species of Bikaner city (Rajasthan)

The air pollution tolerance index (APTI) is one of the modern tools for assessing the impacts of air pollutants on plant physiology. The value of APTI is different for different plant species. Plants with higher values of APTI are tolerant and act as a sink due to their bioaccumulation ability for air pollutants. Hence, they can be planted to establish green belts in areas with severe air pollution, especially in industrial zones. The present investigation was carried out to assess the APTI values of top twenty urban tree species of the Bikaner city of North-Western Rajasthan. The leaf samples were taken from selected roadside trees distributed in the residential, commercial and industrial zones of the city. On the basis of APTI values, it was observed that Leucaena leucocephala (23.41), Eucalyptus camaldulensis (21.87) and Cassia siamea (21.39) had an APTI value above 20 and they are therefore classified as tolerant species. Similarly, Pongamia pinnata (9.48) showed APTI under 10, therefore it falls into the sensitive category. 80 % of the total species in the studied area are categorized as a moderately sensitive category. There were no plant species in very sensitive (APTI < 1) and very tolerant (APTI > 30) category.

Comparative Study of The Physiological Condition of Six Tree Species to Air Pollution in Depok City, West Java

Background: Air pollution is a threat to the environment. Sources of air pollutants in urban environments can be in the form of dust, heavy metals, and hydrocarbons. Plants can help clean air pollutants from the atmosphere by absorption through the stomata, accumulating them, or by adsorption on the leaf surface. The Air Pollution Tolerance Index (APTI) is used as an evaluation benchmark for the Physiological conditions of plants exposed to air pollution. This research aims to study the physiological conditions of six tree species in air conditions in the Depok City area and to assess the plants' tolerance level based on the APTI calculation. Methods: The physiological parameters measured to calculate APTI were ascorbic acid, total chlorophyll, leaf extract pH, and Relative Water Content (RWC). The six tree species used as objects in this study were Artocarpus altilis, Artocarpus heterophyllus, Bauhinia purpurea, Ficus septica, Filicium decipiens, and Nephelium lappaceum. Results: Differences in the physiological conditions of six tree species in the Depok City area based on the average ascorbic acid values, total chlorophyll, leaf extract pH, and RWC. In addition, there are also differences in APTI parameters between the two research locations. Conclusions: Filicium decipiens is the plant species with the highest APTI, while Artocarpus heterophyllus has the lowest. Based on the APTI scores, Bauhinia purpurea, Ficus septica, Filicium decipiens, Nephelium lappaceum belong to moderately tolerant category, Artocarpus altilis belongs to an intermediate category, Artocarpus heterophyllus belongs to sensitive category.

ANALISIS KARAKTERISTIK VEGETATIF DARI EMPAT VARIETAS PADI DALAM PERLAKUAN CEKAMAN KEKERINGAN [Vegetative Characteristics Analysis of Four Rice Varieties Under Drought Stress

Rice plants that are resistant to drought stress and can be grown on dry land, are needed to increase national food security. A method which has been widely used to determine drought tolerance levels of plants is the morphological analysis. The vegetative characteristics analysis of rice varieties thought to be drought-tolerant, such as West Sumba rice varieties (Pare Lambem and Pare Bakato Kaka), INPARI 32 and INPARI 42, is known to have never been done before. This study aims to identify rice varieties that show the highest stress tolerance based on vegetative performance data through drought stress treatments. The research started with germinating seeds in two treatments (control and PEG 6000 20%) for seven days. The germinated seeds were then transferred to the planting medium and watered every three days for samples treated with PEG 6000 20% after 14 DAP (drought treatment). The vegetative performance data was then processed statistically by calculation of the Fernandez index (1993) or the t-test (α<0.05). The results showed that the percentage of germination, radicle weight, and the average number of leaves (35 DAP) in each variety grouped into the tolerant category. For the leaf curvature scores, the Pare Lambem variety is classified into the sensitive category (score 5), while the other three varieties were classified as Tolerant-category (score 1). Plant height and leaf length values at 7 DAP and 35 DAP showed the same pattern as the leaf curvature score that Pare Lambem showed a significant difference between the control and drought treatments based on the t-test (sensitive category). In contrast, other varieties showed a tolerant category. Based on the assessment of several test characteristics, Pare Lambem was classified into the slightly tolerant category (42.8%), while other varieties were classified into the tolerant category (85.7%).

Estimation of air pollution tolerance index of plants in selected locations in Kanpur City, India

One of the world's most critical issues today is air pollution brought on by vehicle emissions, which poses a serious threat to both the environment and the health of living things (plants, humans, animals, microorganisms). Air pollution results from unsustainable, uncontrolled, and rapid development. As the amounts of different gases in the atmosphere increase, the quality of the air is getting worse and worse every day. A major contributor to air pollution is vehicle emissions 3,50,000 automobiles are registered in Kanpur, the eleventh most populous city in India. Plants along the road primarily absorb the majority of toxins released by vehicles. This study aims to determine the resistance and susceptibility of various plant species to air pollution. In the majority of developing countries, one of the causes of air pollution is vehicle emissions. Planting along the side of the road is an important method of reducing the pollution that vehicles emit. The APTI value of the plants is determined by four important biochemical parameters: pH, relative water content (RWC), total chlorophyll (Tch), and ascorbic acid (Asc) content of leaves. Plant leaves were gathered from two separate area of the city: a commercial area (Kanpur cantonment) and an industrial area (Chakeri). According to APTI values, the tolerant plants in the commercial area are Mangifera indica (30.54) and, while the tolerant category plants in the industrial area are Lonicera nigra (37.26), Nerium indicum (36.62) and Azadirachta indica (30.02).

SEASONAL INCIDENCE AND REACTION OF GREENGRAM GENOTYPES AGAINST SPOTTED POD BORER, Maruca vitrata (FABRICIUS)

Greengram cultivation is hampered by various insect pests, among which the spotted pod borer, Maruca vitrata (Fabricius) inflicts extensive damage. Insecticides are widely used to suppress this damage but are found to culminate in undesirable effects in the environment and humans. Exploring and exploiting host plant resistance in the gene pool of crop plants is an effective, ecofriendly alternative approach to manage such insect pests. Considering this, 333 greengram genotypes were gathered and screened under field condition to identify resistance sources against spotted pod borer during Rabi 2020 and Kharif 2021 at Sivapuri village, Chidambaram, Tamil Nadu, India. The larval population and their active webbing were accessed from flower bud initiation to end of crop growth period and per cent pod damage was worked out after harvest. The results of this study revealed that, the larval population and active webbing and per cent pod damage were the least on IC-39301-1 followed by IC-311451 and IC-39301-1 followed by IC-103207 during Rabi 2020 and Kharif 2021 respectively. In both seasons, the larval population, active webbing, and percent pod damage were higher in the genotype IC-39317, followed by IC-103981. Based on per cent pod damage 4 and 10 genotypes were found resistant, while 182 and 175 genotypes were moderately resistant, 70 and 78 genotypes were tolerant, 56 and 63 genotypes moderately susceptible and 21 and 7 genotypes were highly susceptible in Rabi 2020 and Kharif 2021 respectively. The genotypes which were grouped under resistant and tolerant category in both the seasons were selected for further evaluation to develop desirable varieties.

Peran Komunikasi Interpersonal Orang Tua Dual Career Marriage di Surabaya dalam Mengawasi Pembelajaran Daring Anak Remaja Awal di Masa Pandemi Covid-19

Interpersonal communication is one of the communications commonly used to convey persuasive messages and increase intimacy as well as a form of communication that can be a bridge for expressing a thought or opinion so that it can lead to a solutive and positive goal. Interpersonal communication between parents and children can affect the success of children's education. During the COVID-19 pandemic, children's face-to-face learning was shifted to online, this tightened the role of parents in supervising their children because children were required to use automatic gadgets for children to deal directly with the online world for quite a long time. Therefore, the results of research from three family informants show that the role of parents is very important in different ways in each family, some interpersonal communication roles are associated with several functions including affective functions (affection), educational functions, religious functions, protective functions and recreational functions, which helps researchers find out how the role of each dual career marriage parent in supervising children's online learning and from four types of families there are only three types of family that occur in three family informants, namely consensual, pluralistic, protective, none of which is in the tolerant category. This research was conducted in Surabaya using a qualitative descriptive approach and phenomenological methods. The results showed that the type of family determines how the role of parents' interpersonal communication with their children because the role of parents' interpersonal communication in supervising children's learning has an impact on the success rate of children's education.

Exploring the genetic variation for sodicity tolerance in Melia dubia evolved in Indian conditions

AbstractSoil sodicity is one of the major constraints for the success of afforestation worldwide. High sodicity causes poor soil physical conditions and thus adversely affect tree growth and biomass production. However, considerable intraspecific variation for sodicity tolerance exists in most of the trees species. Presently, no information is available on sodicity tolerance in the genotypes of the industrially important Melia dubia tree. Therefore, we examined twenty‐five genotypes of M. dubia, that has evolved in different parts of India, to elucidate mechanisms and identify traits imparting sodicity tolerance in these genotypes. The experimental evidence showed the significant genetic variability and relationships in genotypes for various morphological and physiological traits in response to the sodicity stress. On an average, sodicity stress reduced plant height, collar diameter, and shoot biomass by 15%, 18%, and 60%, respectively. The shoots Na+ concentration had negative correlation with the growth traits. Shoot Na+ ions exclusion was found to increase sodicity tolerance and conferred salt tolerance mechanism in M. dubia. Path analysis revealed that the plant height, collar diameter, number of leaves, and branches were major determinants of shoot biomass production. Cluster analysis validated the genotypes response to sodicity and classified the germplasm into sensitive, moderately tolerant, and tolerant category each consisting of nine, eleven, and five genotypes, respectively. Among genotypes, the MDSS06, MDSS13, and MDSS21 produced greater growth and biomass under sodic stress and indicated good growth potential in such soil. The results showed the presence of a high genetic diversity for salt tolerance in Melia, and the identified genotypes can be considered for strengthening the breeding programs aiming at improving the sodicity tolerance of the species. Our result concluded that genetic variation and breeding approaches using the MDSS06, 13, and 21 genotypes have tremendous potential to improve the growth, biomass, and overall productivity of M. dubia under sodic soil conditions.

EFFECT OF 6-BAP GROWTH REGULATOR ON SEED PRIMING OF SEVERAL BREAD WHEAT VARIETIES UNDER WATER IRRIGATION SALINITY STRESS

Two experiments were carried out under greenhouse conditions at the College of Agriculture - University of Anbar for the spring season 2018, using plastic seedlings containers on sandy soil to study the effect of 6 Benzylaminopurine growth regulator and used at a concentration of 250 mg l-1 on seedlings performance of six varieties of wheat, namely; IBA 99, Bohooth 10, Bohooth 22, Abu Ghraib, Bohooth 158 and Ezz under four levels of saline irrigation water 3.00, 4.50, 6.00 and 7.50 dS m-1 in addition to the comparison treatment distilled water 0 dS m-1. The results of the experiment showed that the low concentrations of salts in the nutrient medium activate the radicle growth in the wheat plant. The seeds of wheat germinated in the irrigated medium were outperformed with salty water 3.00 dS m-1 with the highest averages of the studied traits. Ezz cultivar was the most tolerant category of salinity of irrigation water compared to other cultivars. The results of the experiment also showed that soaking the seeds of wheat with a growth regulator solution 6-Benzylaminopurine contributed to reducing the negative effect resulting from the increase in saline stress in the germination medium which improved the seed germination and seed growth characteristics under saline stress. The research recommends using the Ezz variety in the event of high salinity in irrigation water, as well as treating the seeds with the 6-BAP growth regulator to increase the tolerance of seeds to the stress of irrigation water salinity.

Tolerance of wheat (Triticum aestivum) genotypes to root-lesion nematode (Pratylenchus thornei) in the subtropical grain region of eastern Australia

Practical and statistically sound methods are required to provide reliable assessments of the tolerance to P. thornei of large numbers of wheat genotypes for plant breeders’ selections and growers’ choice of cultivars to sow in the subtropical grain region of eastern Australia. We showed from six experiments that tolerance indices for wheat genotypes as ratios of grain yield from paired high and low P. thornei treatments were highly significantly related to grain yield on P. thornei infested field sites. We then applied factor analytic multi-environment trial (MET) analysis to 29 field experiments that tested 784 unique wheat genotypes for tolerance to P. thornei based on grain yield on infested sites. Tolerance to P. thornei was effectively modelled with three factors rotated to a principal components solution, which accounted for 84.0, 4.7 and 3.6% respectively of the genotype x experiment variance and covariance. We then validated the estimated best linear unbiased predictions based on these three components (PA(1 + 2 + 3)-eBLUPs) as a quantitative tolerance index to predict relative grain yield of wheat genotypes in independent experiments on P. thornei infested sites. The range of PA(1 + 2 + 3)-eBLUPS was subdivided into nine arithmetically equal subranges to provide nine ordinal alpha ratings from very intolerant to tolerant for growers’ sowing guides and to select nine genotypes as P. thornei tolerance checks in future experiments. There was a 60% loss of grain yield between genotypes in the very intolerant category compared with the tolerant category emphasising the need for continued characterisation of wheat for tolerance to P. thornei.

Phytoremediation for urban landscaping and air pollution control-a case study in Trivandrum city, Kerala, India.

Air pollutant concentration of Trivandrum, the capital of Kerala, exceeded the limits of National Ambient Air Quality (NAAQ) standards, according to a study conducted in 2015 by NATPAC. These polluted corridors harbour vegetation on roadsides and traffic islands, planted solely for aesthetic appeal. Analysis of air pollution tolerance levels of existing plants can act as a scientific basis for efficient planning of the urban landscape. Sixty-seven species, including flowering, fruit-bearing, ornamental, shade-providing and timber-yielding species, were screened for their relative resistance to air pollution. Based on leaf pH, relative water content, chlorophyll and ascorbic acid levels, the Air Pollution Tolerance Indices (APTI) of each species were formulated and they were grouped into the following: tolerant, moderately tolerant, intermediate and sensitive groups. Agave americana (18.40), Cassia roxburghii (17.63), Anacardium occidentale (11.97), Cassia fistula (11.60), Mangifera indica (11.59) and Saraca asoca (10.88) may be considered for planting near green spaces like roundabouts and near pollution prone industrial areas, as they belong to tolerant category. Comparison of APTI during summer and monsoon also revealed the stability of Agave americana, Saraca asoca, Ficus benghalensis, Peltophorum pterocarpum, Ficus elastica, Ixora finlaysoniana, Mangifera indica, Canna indica and Delonix regia in maintaining pollution tolerance even during water disparity. Agave americana, Anacardium occidentale, Ficus elastica, Mangifera indica, Syzygium cumini, Ficus benghalensis, Nerium oleander and Ficus benjamina were found to be suited for mass planting, as was evident from their Anticipated Performance Indices (API).

Screening of forty Indian Amaranthus hypochondriacus cultivars for tolerance and susceptibility to tropospheric ozone stress

Tropospheric ozone stress adversely affects crop cultivars growth and productivity variably. The variable response of crop cultivars raised the need for identification of ozone (O3) stress-tolerant cultivars as an adaptive option. In the present study, forty cultivars of Amaranthus hypochondriacus were screened for susceptibility and tolerance to ozone stress. The cultivars were exposed to ambient (AO3) and elevated (EO3) ozone levels in free air ozone enrichment (FAOE) facility and monitored for foliar ozone injury symptoms appearance and yield attributes response. Foliar ozone injury symptoms on Amaranthus cultivars were interveinal yellow or black spots. Foliar ozone injury was observed in almost half of the cultivars and the maximum foliar injury (> 75%) was observed in cultivar IC-5527. The maximum yield reduction (> 90%) was observed in cultivars IC-4200 (94.9%) and IC-5569 (91.4%) compared to other cultivars. The results showed that Amaranthus cultivars exhibited variable response towards ozone stress where foliar ozone injury does not always correspond with grain yield reductions. Among the indices, Relative Yield Index (RYI), Stress tolerance (TOL), Abiotic Tolerance Index (ATI), Susceptibility Index (S) and Stress Susceptibility Index (SSSI) were positively correlated with relative yield loss in all the cultivars under ozone stress. With the help of cluster analysis and principal component analysis (PCA), the cultivars were categorized into ozone tolerant, moderately ozone tolerant and ozone susceptible category. The most tolerant cultivars were IC-5527 and IC-1733 which exhibited lower yield losses whereas the most susceptible cultivars were IC-3599 and IC-7924 having high foliar injury and maximum yield losses as compared to other cultivars. The most ozone tolerant cultivars of Amaranthus identified in this study may be recommended for cultivation to farmers in the areas experiencing EO3 during the Amaranthus crop growth period.

Drought tolerance in Triticum aestivum L. genotypes associated with enhanced antioxidative protection and declined lipid peroxidation.

Drought is one of the major constraints in wheat production and causes a huge loss at grain-filling stage. In this study we highlighted the response of different wheat genotypes under drought stress at the grain-filling stage. Field experiments were conducted to evaluate 72 wheat (Triticum aestivum L.) genotypes under two water regimes: irrigated and drought condition. Four wheat genotypes, two each of drought tolerant (IC36761A, IC128335) and drought-susceptible category (IC335732 and IC138852) were selected on the basis of agronomic traits and drought susceptibility index (DSI), to understand their morphological, biochemical and molecular basis of drought stress tolerance. Among agronomic traits, productive tillers followed by biomass had high percent reduction under drought stress, thus drought stress had a great impact. Antioxidant activity (AO), total phenolic and proline content were found to be significantly higher in IC128335 genotype. Differential expression pattern of transcription factors of ten genes revealed that transcription factor qTaWRKY2 followed by qTaDREB, qTaEXPB23 and qTaAPEX might be utilized for developing wheat varieties resistant to drought stress. Understanding the role of TFs would be helpful to decipher the molecular mechanism involved in drought stress. Identified genotypes (IC128335 and IC36761A) may be useful as parental material for future breeding program to generate new drought-tolerant varieties.

Religious Tolerance of Minangkabau and Batak Ethnic Students in Xaverius Bukittinggi High School

This article is based on the results of a mini-research that aims to describe the religious tolerance of Minangkabau and Batak ethnic students at Xaverius Bukittinggi High School in the academic year 2019/2020. This research uses a quantitative approach. The steps in this research are conducting preliminary studies, literature studies, data collection, data analysts and conclusions. The population of this study, XII Bukittinggi ethnic group Minangkabau and Batak ethics XII grade students. Sampling with purposive sampling technique. Data collection using a questionnaire, data analysis techniques with normality, homogeneity, and T-test. The results of this study illustrate the religious tolerance of ethnic Minangkabau and Batak students dominated by the tolerant category. There was no significant difference in religious tolerance between ethnic Minangkabau and Batak students. However, differences in religious tolerance scores were found between ethnic Minangkabau students and Batak students on the aspect of maintaining independence in practising religion and respecting the practice of diversity. The Batak students are a minority population in Xaverius Bukittinggi high school while the majority are Minangkabau students population. Development of religious tolerance Students of the Minangkabau ethnic group and the Batak ethnic group at Xaverius High School tend to be equally tolerant and potentially more tolerant when the curriculum and education at the school are carried out properly. The results of this study can be used as consideration for developing religious-spiritual strength counselling and arranging cross-cultural counselling and guidance programs in high schools.

Screening of wheat genotypes against salinity at early vegetative stage in pot culture

Experiment was carried out to investigate intraspecific variation for salt tolerance and to classify the wheat genotypes into different salt tolerant groups. Considerable variations among the genotypes in response to salinity were observed for shoot length under 16 dS/m NaCl salinity in the both seasons. Salt tolerant genotype was found to be less affected at high salinity and could be produced better total dry matter compared to other genotypes. Five and seven genotypes appeared as tolerance during 2008 - 09 and 2009 - 10, respectively based on relative total dry matter (RTDM). On the other hand, six and three genotypes exhibited tolerant during 2008 - 09 and 2009 - 10, respectively based on visual scoring. The distribution pattern of the genotypes into various salinity tolerant groups remained fairly constant under two methods. Three genotypes G24, G33 and G40 exhibited tolerant category. RTDM compared to the control would be very useful trait in salinity tolerant improvement programme. However, visual scoring provide guidelines for mass screening of salt tolerant genotypes.

Evaluation of Chrysanthemum morifolium varieties for salinity tolerance under hydroponic system

Salinity tolerance of 22 varieties of chrysanthemum (Chrysanthemum morifolium Ramat.) was studied in National Phytotron Facility, ICAR-Indian Agricultural Research Institute, New Delhi at five different salinity levels (0, 50, 100, 150, 200 mmol/L). Salt tolerance was identified by measuring changes of different physiological as well as morphological parameters such as chlorophyll, proline, MSI (Membrane Stability Index), shoot length, root length, dry weight, etc. In the present study, it was found that the amount of chlorophyll a, chlorophyll b and total chlorophyll decreased with increase in the amount of salt concentration. At 100 mmol/L NaCl, the highest total chlorophyll content was found in Pusa Aditya, Haldighati, Lalit, Little Pink and Jaya, whereas lowest was observed in Pusa Sona, Yellow Gold and Himanshu. The rate of reduction in dry weight is dependent on the level of stress and variety. The greatest reduction in dry weight was found under 200 mmol/L NaCl treatment. The MSI reduced up to 47.64% under 200 mmol/L NaCl treatment from 85.65% of control. Reduction in MSI with increase in salinity may be due to high electrolyte leakage from cells of susceptible varieties. An increase in Proline content was observed under salt treated plants as compared to the plants under control. There was significant decrease in the root length with increase in the salt concentration. On the basis of modified standard evaluation score (SES) of visual salt injury, the 22 varieties can be grouped into tolerant, moderately tolerant, susceptible and highly susceptible with most of the varieties falling under the category of moderately tolerant. Little Pink, Lalit, Haldighati and Pusa Aditya falling under the tolerant category while Himanshu and Pusa Sona are grouped under susceptible and highly susceptible category respectively.

Growth and salinity tolerance of wheat genotypes at early vegetative stage

Growth and salinity tolerance study of wheat genotypes were conducted at regional agricultural research station to evaluate the selected wheat genotypes against salinity and to classify the wheat genotypes in different salt tolerant group. The experiment was carried out with 12 wheat genotypes under semi-controlled environment (inside plastic greenhouse) and natural light in a randomized complete block (RCBD).The materials were evaluated under control (non-saline) and 16 dS/m salinity level. A significant variation among the genotypes was observed for shoot length under both environments. The lowest reduction (2%) was found from G11 followed by G40 (4%). The genotypes showed differences in production of total shoot dry matter (TDM) at both non-saline and saline conditions. The relative TDM per plant (% TDM to control condition) appears that three genotypes (G24, G33and G40) produced 90% RTDM. Salt tolerant genotype was found to be less affected at high salinity and could be produced better TDM compared to other genotypes. Three genotypes G24, G33 and G40 exhibited tolerant category. The distribution pattern of the genotypes into various salinity tolerance groups indicates that the overall pattern of behaviors of the genotypes tested remain fairly constant under two methods (based on RTDM and visual scoring).Progressive Agriculture 28 (1): 12-17, 2017

The impact of gasoline emission on plants – a review

ABSTRACTThis review presents the status of knowledge about gasoline exhaust pollution and its impact biochemical and physiological characteristics of plants. Parameters on such as leaf conductance, membrane permeability, ascorbic acid, chlorophyll and relative water content have been used as indicators to assess the impact of gasoline exhaust pollution on plant health. Tolerant plants such as Mangifera indica Linn. are reported showing an insignificant decrease in the percentage of chlorophyll content (3.6%) and a significant increase in the percentage of ascorbic acid (84.6%) and sensitive plants such as Cassia fistula are reported showing a significant decrease in the percentage of chlorophyll (66.4%) as well as ascorbic acid (32.9%). In the case of ornamental plants, Dracaena deremensis has been reported to show an insignificant decrease in the chlorophyll content but a significant increase in the ascorbic acid, pH and relative water content, which were found to be in tolerant category, while Dianthus caryophyllus showed sensitive characteristics. Such plants can be used as sinks and bioindicators for gasoline exhaust pollution. Though several studies reported biochemical impacts of individual or combined exhaust gases on plant species, the cumulative effect of gasoline exhaust on plant species has not been studied extensively, especially in the developing countries.

Yield, Vegetative Growth, and Fiber Length of Kenaf Grown on Saline Soil

AbstractKenaf (Hibiscus cannabinus L.) is an excellent supplement to wood as a source of fiber for paper pulp. With the introduction of kenaf into the western USA, plantings may be on soils where salinity problems already exist or may develop from the use of saline irrigation water. Because of the lack of salt‐tolerance information on mature vegetative growth and yield, a 2‐yr field‐plot study was conducted at Brawley, CA. Two cultivars (Everglades‐41 and 7818‐RS‐10) were grown with six salinity treatments imposed on a Holtville silty clay [clayey over loamy, montmorillonitic (calcareous), hyperthermic Typic Torrifluvent]. Electrical conductivities of the irrigation waters, containing NaCl and CaCl2 (1:1 by weight), were 1.1, 2.0, 3.0, 4.0, 5.0, and 6.0 dS m−1. Soil salinity (electrical conductivity of the saturated‐soil extract, Kc) ranged from 5.4 to 12.6 dS m−1 the first year, and from 6.0 to 14.9 dS m−1 the second year. Vegetative growth, stem yield, and fiber length were measured. The mean dry weight yields of the stems during the 2‐yr experiment were reduced 11.6% for each unit increase in soil salinity above 8.1 dS m−1. These results place kenaf in the salt tolerant category. Yield reduction resulted from both a reduction in plant height and stem diameter. Increased salinity did not significantly affect fiber length. Excessive Cl accumulation occurred in the leaf tissues at high soil salinity levels.

Reduction in growth and yield of Jerusalem artichoke caused by soil salinity

The salt tolerance of irrigated Jerusalem artichokes (Helianthus tuberosus L.) was assessed in terms of biomass of both above ground parts and tubers in greenhouse and field trials. Salinity of irrigation water ranged from 0.7 to 12 dS m−1 in the greenhouse trial and from 0.2 to 10 dS m−1 in the field trial. Yield response of the dry matter of tubers of greenhouse-grown plants and of above ground parts of greenhouse-grown and fieldgrown plants, fell within the moderately tolerant category of Maas and Hoffman (1977). However, tuber yields in the field on a heavy clay loam fell within the moderately sensitive category, described by the equation, Y = 100 − 9.62 (ECe-0.4), where Y = yield (t ha−1) as a % of that under non-saline conditions and ECe = electrical conductivity of saturation extract in the rootzone (0–30 cm). The Cl concentration of leaves increased linearly with increasing external salinity and increased from tubers to stems to leaves. In contrast, leaf Na remained low except at the highest salinities, despite consistently higher stem Na; indicating some mechanism for restriction of leaf Na up to a certain external salinity.

Salinity Effects on Emergence, Vegetative Growth, and Seed Yield of Guar

AbstractGuar [Cyamopsis tetragonoloba (L.) Taub] seed is an important source of galactomannan gum used in food and industrial products. Increased demand and an insufficient domestic supply has led to an increased interest in this crop in the semi‐arid western USA where many soils are, or have the potential to become, highly saline. This study was conducted to determine the effect of soil salinity on vegetative growth and seed yield of two cultivars, 'Kinman' and 'Esser,' grown under field conditions. Six salinity treatments were imposed on a Holtville silty clay [clayey over loamy, montmorillonitic (calcareous), hyperthermic Typic Torrifluvent] by irrigating with waters salinized with NaCl and CaCl2 (1:1 by weight). Electrical conductivities of the irrigation waters were 1.3, 2.5, 5.0, 7.4,10.0, and 12.4 dS/m during the 1st yr, and 1.2, 2.5, 4.5, 5.5, 6.5, and 7.5 dS/m during the 2nd yr. Seed yield of both cultivars was unaffected by soil salinity up to 8.8 dS/m (mean electrical conductivity of the saturated‐soil extracts in the rootzone). Each unit increase in salinity above 8.8 dS/m reduced seed yield by 17%, which places guar in the moderately tolerant category for seed production. Reduction in the number of pods per plant and weight per seed were the primary factors contributing to reduced yields. Vegetative growth was decreased 9.6% for each unit increase in salinity above 4.9 dS/m. Plant emergence was determined in greenhouse sand cultures with irrigation waters of 0.8, 4.4, 8.5,11.3,15.7, and 18.8 dS/m. Emergence was unaffected by salt levels up to 8.5 dS/m; greater levels delayed but did not significantly reduce the percent emerged.