Unravelling physiological and biochemical attributes influencing post harvest quality of gladiolus spikes after packaging and low temperature storage

The perishable nature of flowers urge for their appropriate post harvest management especially storage and packaging that keep the quality and potential vase life for better value. Gladiolus, commonly called as Sword lily, is a commercially important cut flower crop with elegant spikes, bright florets and good keeping quality. In the present study, we investigated the physiological and biochemical attributes affecting post harvest life of gladiolus spikes after packaging and storage. The spikes of four gladiolus cvs. Punjab Glance, Punjab Glad-1, Punjab Glad-2 and Punjab Pink Elegance were harvested at tight bud stage and packed in PP sleeves (25 ?m) and stored vertically at 4-5°C for 6, 9 and 12 days. After storage, the post harvest quality of both packed and unpacked spikes declined with more adverse effect on unpacked spikes. Among different storage durations, the spikes stored for 9 days showed good keeping quality parameters viz., vase life, per cent flower opened, floret size, days to opening of basal floret, maximum number of florets open at one time and water absorbed per spike which were at par with spikes stored for 6 days. The spikes stored for 12 days were found to be unacceptable in comparison to freshly harvested spikes and spikes stored for 6 and 9 days. The improved quality of spikes stored in sleeves could be accounted due to higher membrane stability index, relative water content, catalase and peroxidase activity as compared to unpacked spikes. Thus, loss in quality of spikes as compared to fresh during storage up to 9 days in PP sleeves is better than the complete loss of produce during transportation and gluts. Hence, the spikes of gladiolus could be stored dry at 4±0.5°C in PP sleeves for 9 days without much influence on its post harvest quality.

Evaluation of potential of portable chlorophyll meter to quantify chlorophyll and nitrogen contents in leaves of wheat under different field conditions

The chlorophyll meter is a simple, non destructive and portable tool that could be used to measure the greenness or relative chlorophyll and nitrogen contents in leaves during different developmental stages for efficient nutrient management. In this study, we tried to correlate SPAD index with chlorophyll (chl)/nitrogen(N) content in leaves of bread wheat (Triticumaestivum L., PBW 509) and durum wheat (Triticum durum L. PDW 233), and to find the variable (chl concentration i.e. µg Chl g-1 tissue, content i.e. µg Chl cm- 2 tissue or N content) that could be best estimated with chlorophyll meter.The leaf samples collected from four different fields varying in N and manganese fertility levels, exhibited a wide range of SPAD index (26-47).The linear model was best fitted to describe the relationship of these variables with SPAD index and it was found to be the best measure of chl concentration (R2= 0.59) as compared to chl content (R2= 0.49) and nitrogen content (R2= 0.37). The correlations improved when separate calibration curves were plotted for cultivar and field. SPAD index explained 70, 87 and 71% of variation in chl concentration, chl content and N content, respectively, at field 3 from pooled data of the two cultivars and the corresponding values of variables were 94, 93 and 91% for PBW 509 and 87, 83 and 91% for PDW 233 from pooled data of four fields. The chlorophyll meter can be used with caution to develop separate calibration curves for particular cultivar, field, hybrid and treatments to develop standards for interpretations and efficient fertilizer management.

Manganese influx and its utilization efficiency in wheat.

Manganese deficiency in wheat has become an important nutritional disorder particularly in alkaline calcareous soils where rice-wheat rotation is followed. This experiment was aimed to study the mechanism of Mn efficiency during various developmental stages in six wheat cultivars grown at two Mn levels viz. 0 and 50 mg Mn kg-1soil (Mnapplied as MnSO4.H20) in pots. The Mn vegetative efficiency calculated on the basis of shoot dry weight at anthesis indicated HD 2967 and PBW 550 (bread wheat) as Mn efficient and durums as Mn inefficient. The efficient cultivars recorded highest values for influx, uptake, shoot dry weight, leaf area/plant, SPAD index, Fv/Fmratio and root length that explained their higher efficiencies whereas inefficiency of durum cultivars was attributed to their smaller roots and lower influx. Under Mn deficiency, PDW 314 and PDW 291 retained 68% and 64%, respectively, of total Mn uptake in vegetative parts (stem and leaves) and lowest in grains 7% and 5%, respectively, whereas PBW 550, BW 9178 and HD 2967 retained 29, 37 and 34% in vegetative parts, and 21, 17 and 15 % in grains, respectively at maturity. Higher utilization efficiency of efficient genotypes also indicated that increased Mn uptake with Mn supply produced more efficiently grains in efficient genotypes but vegetative parts in inefficient genotypes. Hence Mn efficiency of a cultivar could be explained by longer roots, higher uptake, influx and efficiency index during vegetative phase and higher grain yield and utilization efficiency during generative phase.

Role of nitric oxide in cadmium-induced stress on growth, photosynthetic components and yield of Brassica napus L.

Experiments were carried out to study the effect of cadmium (Cd) and exogenous nitric oxide (NO) on growth, photosynthetic attributes, yield components and structural features of Brassica napus L. (cv. GSL 1). Cadmium in the growth medium at different levels (1, 2 and 4 Mm) retarded plant growth viz. shoot (27%) and root (51%) length as compared to control. The accumulation of total dry matter and its partitioning to different plant parts was also reduced by 31% due to Cd toxicity. Photosynthetic parameters viz., leaf area plant-1 (51%), total Chl (27%), Chl a / Chl b ratio (22%) and Hill reaction activity of chloroplasts (42%) were greatly reduced in Cd-treated plants. Cd treatments adversely affected various yield parameters viz., number of branches (23) and siliquae plant -1 (246), seed number siliqua -1 (10.3), 1000-seed weight (2.30g) and seed yield plant-1 (7.09g). Different Cd treatments also suppressed the differentiation of various tissues like vessels in the root with a maximum inhibition caused by 4mM Cd. Exogenous application of nitric oxide (NO) improved the various morpho-physiological and photosynthetic parameters in control as well as Cd- treated plants.