Loss Of Green Color Research Articles

Changes in peel pigmentation during ripening of mango fruit (Mangifera indica var. Tommy Atkins)

SUMMARYThe pigments in the peel of Tommy Atkins mango were analysed at six stages during ripening at 22 oC. The loss of green colour and the development of yellow colouration was associated with an almost complete loss of chlorophyll and an increase in carotenoids. Anthocyanin content showed a slight decrease during ripening. An ultrastructural study showed plastids in green fruit with a well developed grana network system. On ripening the chloroplasts underwent extensive disorganisation which was associated with the development of large osmiophilic globules.

Selection for Time to Maturity in Spring Wheat1

Numerous methods have been used to measure time to maturity in spring wheat, Triticum aestivum L. In this study, the time to complete loss of green color from the spike was used as the basis for evaluating effectiveness of selection for time to maturity and for identifying alternative selection criteria. Time to maturity and 11 other traits were measured on 50 F2‐derived F3, lines in each of six crosses tested in replicated dryland and irrigated field trials. High heritabilities and high genotypic correlations with time to maturity indicated that time to full flag‐leaf emergence, times to beginning or completion of spike emergence, time to anthesis, spike moisture, and number of leaves could be used as selection criteria for time to maturity. Bidirectional selection for time to maturity (10% selection intensity) showed that selection was more effective in some crosses than in others, and under irrigated rather than dryland conditions. Realized heritability for time to maturity varied from −8 ± 21% to 186 ± 50% depending on cross and environment. Bidirectional selection for number of leaves (6% selection intensity) confirmed that this characteristic is a reliable criterion for altering time to maturity. With selection differentials of 0.95 to 2.64 leaves, correlated response for time to maturity varied from 40 to 119 growing degree‐days. Number of leaves and spike moisture concentration are useful methods for evaluating maturity when developmental stages cannot be measured at frequent intervals.

A Systems Approach to the Evaluation of Changes in Quality During Postharvest Handling of Southern Peas

A systems approach was used to identify the step(s) which result in the greatest loss of quality during postharvest handling of southern peas. A maturity index was used to separate effects of handling and maturity on quality loss. In‐field holding of the peas during truck loading is the most critical step in postharvest quality of southern peas. Attempts to control quality during transit from field to processing plant will be ineffective if proper control does not start during loading. Immature peas are more susceptible to loss of green color while more mature peas accumulate more lactic acid during handling. Use of a systems approach has ready applicability to the study of handling of fresh and processed fruit and vegetable products.

Physiological maturity in Aestivum wheat: visual determination

SummaryField experiments were conducted during the winter seasons of 1977–8 and 1978–9 at Agronomy Research Area of Haryana Agricultural University Farm, Hissar, to identify the visual plant characters that coincide with physiological maturity (PM) and 95% maximum grain dry weight (95% MGW) in wheat (Triticum aestivum L.) cultivars. The dry-weight accumulation data from three cultivars (WH-157, HD-2009 and UP-270) differing in many agronomic characters were fitted to polynomial regression equations to calculate time of PM and 95% MGW. The mean number of days from anthesis to 95% MGW and from anthesis to PM ranged from 31 to 36 and 38 to 43, respectively, depending upon cultivar. The time of 95% MGW preceded PM by about 7 days. Of the nine visual plant characters recorded during the grain-filling period, complete loss of green colour from the glumes occurred close to PM. Complete loss of green colour from the flag leaf most consistently coincided with the time of 95% MGW. Complete loss of green colour from the flag leaf could therefore be used as an indicator of the commencement of rapid decrease in grain dry weight and the final stage of grainfilling which ends when the glumes have lost the whole of their green colour.

PREHARVEST DESICCATION OF GREEN-SEEDED FIELD PEAS WITH DIQUAT

Diquat treatments were applied to green-seeded field peas (Pisum sativum L.) over a 5-yr period to determine the effect of applications at various stages of maturity on some agronomic and quality characteristics. The spray application effectively hastened drying of the plants, eliminating the need for windrowing. The rate of 0.28 kg a.i./ha was adequate. The earlier harvesting permitted by the treatments reduced loss of green color and germinability associated with weathering and reduced yield loss from shattering. Applications made as early as the 50% brown pod stage did not markedly affect yield, protein content, seed size, cooking quality or germinability. However, a later stage of spraying may be advisable under conditions of slow maturation.

Visual Indicators of Physiological Maturity of Hard Red Spring Wheat1

Field experiments were conducted in 1979 and 1980 to identify visual indicators that coincide with physiological maturity (PM) and 95% maximum kernel dry weight (95% MKW) in hard red spring wheat (Triticum aestivum L.). Dates of PM and 95% MKW were calculated from polynomial regression equations fitted to dry weight accumulation data from eight genotypes differing in several agronomic traits. In 1980, kernels were divided into three groups according to their position on the spike (bottom, middle, and top) to determine the order in which kernels achieve their maximum dry weight.The mean number of days from anthesis to 95% MKW and PM ranged from 22.3 to 33.7 and 27.9 to 40.1, respectively, depending upon planting date and genotype. Kernels matured, in order, from the top of the spike down. The time of 95% MKW preceded PM by about 7 days. Of the 13 visual characteristics observed during the grain‐filling period, first appearance of the pigment strand in the crease most closely coincided with the calculated date of PM. Complete loss of green color from the glumes also occurred close to PM. Complete loss of green color from the flag leaf most consistently coincided with the time of 95% MKW. An abrupt drop in kernel moisture content also occurred at 95% MKW. Complete loss of green color from the flag leaf could, therefore, be used as an indicator of the commencement of rapid kernel dry‐down and the final stage of grain filling which ends when the pigment strand is first visible and the glumes have lost all green color. Kernel moisture percentage at PM and 95% MKW was too variable to be considered a reliable indicator of either PM or 95% MKW.

A Whole‐plant Indicator of Soybean Physiological Maturity1

Loss of green color from the pod has been suggested as an indication of physiological maturity for individual soybean [Glycine max (L.) Merrill] seeds. In this study, we evaluated the usefulness of green pod color loss as an indicator of the physiological maturity of an entire soybean plant. We also studied the relationship of this visual change to other stages of whole‐plant soybean development and maturity already in use or described in the literature. The study was conducted in 1978 and 1979 at St. Paul, Minn. on a well‐drained Waukegan silt loam (sandy‐skeletal, mixed mesic Typic Hapludolls). The 1st year, cvs. ‘McCall’ (Group 00) and ‘Hodgson 78’ (Group I) were used. In 1979, ‘Altona’ (Group 00) and ‘Steele’ (Group I) were added. Seed dry weight was measured at 1‐week intervals for 8 weeks which spanned the maturation phase. The calculated date of physiological maturity was then related to a variety of visual plant changes.Loss of green pod color was found to be the most reliable indicator of physiological maturity across years, cultivars, and maturity groups. Stage R7 according to Fehr and Caviness (occurs when one normal pod on the main stem has reached its mature color) was next most reliable, but occurred before physiological maturity and interacted with years. The ‘all pods brown’ stage occurred midway between physiological maturity and harvest maturity (harvest maturity = average seed moisture at 13%). On the average, early maturing seeds reached physiological maturity 11 days before late maturing seeds. Seed moisture content averaged 44% when the entire plant was physiologically mature. Color of petioles and stems, and color or senescence of leaves were not reliable indicators of physiological maturity.

QUALITY, YIELD, AND SEED WEIGHT OF GREEN FIELD PEAS UNDER CONDITIONS OF APPLIED SHADE

Field studies were conducted in 1973 and 1974 to evaluate the effects of light intensity on the quality and yield of the green field pea (Pisum sativum L.) ’Triumph’. The treatments included a control with no shading (80 klx) and shading with one (31 klx) or two (9 klx) layers of screen material for a 3-wk period before maturity. Shading resulted in a significant decrease in seed weight and yield and a significant increase in protein content of the seed. The effect of shading on viscosity of the cooked samples was quadratic, implying that viscosity only decreased at very high levels of shading. Shading also tended to reduce loss of green color in the seed cotyledons.

A Visual Indicator of the Physiological Maturity of Soybean Seed1

The objective of this study was to identify a visual indicator of the physiological maturity (PM) of soybean (Glycine max [L.] Merrill) seeds. Six soybean cultivars with different seed colors at maturity were grown in the field for 2 years, and the date of maximum seed dry weight accumulation at nodes seven, eight, and nine was determined. Visible seed, pod and leaf charactexistics throughout the maturation process were recorded. Maximum seed dry weight occurred when the seeds had an average of 58% moisture. Of the 11 selected visible criteria, the one that coincided consistently with the determined date of PM was the initiation of seed shrinkage. The complete loss of green color from the pod was also a reliable indicator of PM since it always occurred in the sampling period immediately following observed seed shrinkage. Because the determined date of PM in this study could have been slightly premature, the loss of green color in the pods might be considered the better indicator of seed PM. Loss of green color from the pods would be a convenient and rapid field determination of PM.

The Effect of Temperature and Relative Humidity During Degreening on the Colouring of Shamouti Orange Fruit

SummaryDegreening and colour development in Shamouti oranges were faster at 25°C than at 20°C. Higher temperatures (30°-35°C) accelerated the loss of green colour but the fruits became pale yellow colour only. A higher temperature thus appears to be beneficial only during early degreening, when the level of chlorophyll is high and of carotenoids low. Different relative humidities during degreening did not affect colour development, but slightly affected weight loss and the drying of degreened buttons.

Fluoride injury symptoms in epiphytic lichens and mosses

This study was conducted in Arvida, Quebec, where volatile fluorides and HF are released into the atmosphere from an aluminum factory. Lichen and moss-bearing bark discs, cut out from trees in an unpolluted area, were fixed in groups of six in rectangular wooden boards. All discs were photographed in color as well as in black and white. Fifteen sites, in addition to a control site, were selected in different directions from the factory. At each site two boards were fixed with nails in a vertical position at a height of 8–10 m on a tree. One board was removed after 4 months exposure and the other after 12 months. The lichens and mosses exposed in control and polluted areas were compared with respect to their color, external morphology, plasmolysis in algal cells, loss of green color, the nature of reactions towards neutral red and 2,3,5-triphenyl-2H-tetrazolium chloride (TTC), absorption spectra of chlorophyll, and fluoride concentration. Results indicate that F-pollution affects moisture balance, causes chlorophyll damage, and produces other symptoms of injury which could lead to ultimate death of these organisms.

Effect of different iron-, potassium-, phosphate-, and calcium-manganese relationships on the growth and chemical composition of aromatic strain of bidi tobacco (Nicotiana tabacum L.)

In order to study the Mn nutrition ofbidi tobacco plant (Nicotiana tabacum L. aromatic strain 2-1) when it is supplied with nutrient solutions containing different ratios of Mn with Fe, P, K and Ca, a sand-culture experiment was carried out in four different series viz. Fe-Mn, K-Mn, P-Mn and Ca-Mn. No characteristic deficiency symptoms except general loss of green colour and diminished growth were observed at 0.1 ppm Mn in the nutrient solution. Toxicity was observed when Mn in the nutrient solution was 100 ppm and severity of the symptoms decreased with increase in Fe-Mn or K-Mn ratios, but it increased when P-Mn ratio increased while in Ca-Mn series it first decreased and then increased at still higher concentration of Ca on account of chloride ion effect as CaCl2 had to be added to bring about 500 ppm concentration of Ca necessary for the treatment. No symptoms of deficiency or toxicity were observed when Mn in nutrient solution varied from 1 to 10 ppm and Fe-Mn ratio for the leaf varied from 0.4 to 6.1 and its Mn content varied from 190 to 1575 ppm. Slight loss of green colour and plant vigour appeared when Fe-Mn ratio for the leaf was higher than 12.8 even though the Mn content was as high as 90 ppm. Toxic effect due to excessive Mn was felt when Fe-Mn ratio was 0.35 or less and leaf content 1875 ppm or more. Nicotine content was inversely related to the intensity of Mn-toxicity.

Experiments on Photoperiodism, Dormancy, and Leaf Age and Abscission in Sugar Maple

1. A seedling population of sugar maple (Acer saccharum Marsh.), derived from two native seed trees in southeastern Wisconsin, was grown for 7 years (1941-1947) in pots in the University of Chicago greenhouses and gardens. The experimental variables were mainly length of photoperiod and amount of winter chilling, studied particularly in relation to leaf senescence and abscission, onset and completion of bud rest, budbreak, and amount of terminal growth. 2. It was concluded that in this species the loss of green color and leaf abscission under natural conditions are basically conditioned by the naturally decreasing autumnal photoperiod. In the various years and experiments leaves expanding from as early as February to as late as August were mostly abscised in October and November if the plants were maintained on natural photoperiod, either indoors or out. Chronological age of leaves had a limited relation to time of senescence and abscission, youngest leaves persisting a few days longer. Constant photoperi...