Exogenous salicylic acid-induced drought stress tolerance in wheat (Triticum aestivum L.) grown under hydroponic culture

Wheat is an important cereal crop, which is adversely affected by water deficit stress. The effect of induced stress can be reduced by the application of salicylic acid (SA). With the objective to combat drought stress in wheat, an experiment was conducted in greenhouse under hydroponic conditions. The treatments consisted of (a) no drought (DD0 = 0 MPa), mild drought (DD1 = -0.40 MPa) and severe drought (DD2 = -0.60 MPa) by applying PEG-8000, (b) two contrasting wheat varieties Barani-17 (drought tolerant) and Anaj-17 (drought-sensitive), and (c) foliar treatments of salicylic acid (0, 50 mM, 75 mM, and 100 mM). Evaluation of wheat plants regarding biochemical, physiological, and morphological attributes were rendered after harvesting of plants. Statistically, maximum shoot and root fresh and dry weights (18.77, 11.15 and 1.99, 1.81 g, respectively) were recorded in cultivar Barani-17 under no drought condition with the application of SA (100 mM). While, minimum shoot and root fresh and dry weights (6.65, 3.14 and 0.73, 0.61 g, respectively) were recorded in cultivar Anaj-2017 under mild drought stress without SA application. The maximum shoot length (68.0 cm) was observed in cultivar Barani-2017 under no drought condition with the application of SA (100 mM). While, maximum root length (59.67 cm) was recorded in cultivar Anaj-17 under moderate drought stress without application of SA. Further, minimum shoot length (28.67 cm) was recorded in Anaj-17 under moderate drought stress without SA application. Minimum root length (38.67 cm) was recorded in cultivar Barani-17 under no drought condition without SA application. Furthermore, maximum physio-biochemical traits, including membrane stability index (MSI), chlorophyl content, photosynthetic rates, stomatal conductance, antioxidant enzymatic activities and relative water content (RWC) were found highest in cultivar Barani-17 under no drought stress and SA application at 100 mM. However, minimum values of these traits were recorded in cultivar Anaj-17 under severe drought stress without SA application. Our results also demonstrated that under severe drought, application of SA at 100 mM significantly increased leaf nitrogen (N), phosphrus (P) and potassium (K) contents and cultivar Barani-17 demonstrated significantly higher values than Anaj-17. The obtained results also indicated that the cultivation of wheat under drought stress conditions noticeably declines the morphological, physiological, and biochemical attributes of the plants. However, the exogenous application of SA had a positive impact on wheat crop for enhancing its productivity.

Kaolin application to increase lettuce (Lactuca sativa) growth under suboptimal watering condition

Lettuce is a crop sensitive to water availability as it needs more water in cultivation. Kaolin has been reported to reduce the impact of drought stress in plants. However, the use of kaolin to increase lettuce growth under drought condition has not been reported yet. In this study, the effect of kaolin to increase the growth of lettuce under suboptimal watering condition was investigated. Kaolin foliar application (3%, 5%, and 6%) was tested on a group consisting of 5 lettuce plants grown under reduced watering condition in a greenhouse. Lettuce height, number of leaves, root length, leaf length and width, fresh and dry weight of lettuce, and leaf chlorophyll content were observed. Kaolin applications significantly increased the growth of lettuce in most parameters compared to the negative control (reduced watering condition, without kaolin). Kaolin 3% application presented the best treatment to increase growth parameters. All kaolin applications did not affect chlorophyll content significantly under lower watering condition. In conclusion, kaolin was able to reduce the impact of reduced watering condition and increase lettuce growth but showed no effect on the leaf chlorophyll content. Thus, further evaluation of kaolin application in lettuce under drought condition is needed.

Water balance studies for the crop planning in Ranchi, Jharkhand

The rainfall data of 35 years was analyzed to quantify the rainfall efficiency for increased production for Ranchi region. The actual evaporation in driest year due to prolonged dry spell gives rise to severe drought condition affecting the crop growth adversely. No surplus water was recorded during driest year. In respect of coefficient of variation, the month of July registered the lowest coefficient of variation of 35 per cent followed by August (38 per cent) indicating lesser variability during this month. The threshold level of coefficient of variation ranges of 50-100 per cent was associated with April to October and indicated the dependability of rainfall in these months as compared to other months. The maximum length of growing season of 28 week, while minimum 12 week was recorded. In normal conditions, the length of growing season were recorded 18 week. Therefore, short duration paddy variety Birsa Gora-101, maize, i.e., Devki, Ganga-11, Suran and kharif pulses are suitable for the region.

Sucrose Metabolism in Plants under Drought Stress Condition: A Review

Drought stress reduces photosynthetic rate and leading to depletion of the energy source and lowers the yield. Under drought stress, reduced turgor pressure cause inhibition of cell elongation and impaired mitosis leads to reduction in growth rate. Role of sucrose metabolism under drought adaptation and response of plants to stress in different tissues and at different developmental stages. Cytoplasmic sucrose synthesis is more under drought condition and there is differential expression in tolerant and susceptible cultivars. Under drought condition, plant start consuming its own sink for its survival thus reducing sucrose concentration. But reduction in sucrose concentration is less in drought tolerant plants. Drought stress induced an increase of the root/shoot ratio, which was due to the increased inhibition of biomass accumulation of shoots compared to roots. Drought stress enhanced the activities of sucrose metabolic enzymes and up-regulated the expression of genes such as SPS, SuSy and INV. In addition, drought stress up-regulated the expression levels of SWEET and SUC and promoted the transport of sucrose from source to sink.