Shirish Chandra Agarwala

Zinc deficiency and pollen fertility in maize (Zea mays)

Zinc deficiency decreased pollen viability in maize (Zea mays L. cv. G2) grown in sand culture. On restoring normal zinc supply to zinc-deficient plants before the pollen mother cell stage of anther development, the vegetative yield of plants and pollen fertility could be recovered to a large extent, but the recovery treatment was not effective when given after the release of microspores from the tetrads. If zinc deficiency was induced prior to microsporogenesis it did not significantly affect vegetative yield and ovule fertility, but decreased the fertility of pollen grains, even of those which visibly appeared normal. If the deficiency was induced after the release of microspores from the tetrads, not only vegetative yield and ovule fertility but pollen fertility also remained unaffected.

Development and enzymatic changes during pollen development in boron deficient maize plants

Abstract Maize (Zea mays L.) plants subjected to severe deficiency of boron (0.0026 ppm B) failed to produce tassels with functional flowers. In plants subjected to moderate deficiency of boron (0.013 ppm B), emergence of tassels and anthesis was suppressed and delayed. In a large percentage of boron deficient plants the stamens lacked sporogenous tissue and appeared as staminodes or floral appendages that either lacked or had branched vascular supply. The apparently normal stamens of these plants also failed to dehisce and showed a marked decrease in pollen producing capacity, pollen size and pollen germination. Even in plants that were only marginally deficient in boron (0.066 ppm B), without any foliar symptoms of boron deficiency, pollen grains showed poor germination and changes in enzyme activities. Pollen grains of such plants had low activities of catalase, acid phosphatase, starch phosphorylase and invertase and high activities of ribonuclease and amylase.

Manganese deficiency in maize affects pollen viability

Maize (Zea mays L. cv. G2) was grown with 0.55 mg L−1 (sufficient), or 0.0055 mg L−1 (deficient) manganese in sand. Manganese-deficient plants developed visible deficiency symptoms and showed poor tasseling and delayed anther development. Compared to Mn-sufficient plants, Mn-deficient plants produced fewer and smaller pollen grains with reduced cytoplasmic contents. Manganese deficiency reduced in vitro germination of pollen grains significantly. Ovule fertility was not significantly affected by Mn. But in Mn-deficient plants seed-setting and development was reduced significantly.

Influence of Changes in Manganese and Magnesium Supply on Some Aspects of Wheat Physiology

Abstract Wheat (Triticum aestivum L.) cv. UP 2003 was grown in refined sand at three levels of manganese, 0.02 (deficient), 10 (adequate), and 200 (high) μM, each at three levels of magnesium, 0.02 (deficient), 2 (adequate), and 4 (excess) mM. In wheat magnesium deficiency aggravated the effects of low manganese supply namely decreases in dry weight, seed yield, chlorophyll content, Hill reaction activity, contents of DNA and RNA, and activities of ATPase and DNAse. On the other hand, the decrease in the activity of RNAse and increase in that of peroxidase were less pronounced in the combined deficiencies of manganese and magnesium than in manganese deficiency. Excess Mg accentuated the visible symptoms of Mn deficiency. Excess Mg also alleviated the effects of high manganese level by increasing the biomass, contents of chlorophyll, DNA, and RNA, Hill reaction activity, and activities of peroxidase and DNAse and by decreasing further leaf Mn content. It appeared that manganese could not replace the role o...

Metabolic changes associated with boron-calcium interaction in maize

Maize (Zea mays L.) cv. T42 was grown in refined sand at low (0.1 μM) and normal (30 μu) concentrations of boron each under low (1 mM), normal (4 mM), and excess (8 mM) supply of calcium. Visible symptoms of boron deficiency which appeared first, were accentuated by calcium deficiency and were least evident when calcium was added in excess. The yield was maximum at normal levels of boron and calcium and was the lowest under boron and calcium deficiency. In maize leaves when both calcium and boron were deficient together the activity of starch phosphorylase increased markedly and that of ribonuclease and polyphenol oxidase also increased. The increase in the calcium content inhibited the starch phosphorylase activity when boron was deficient. The activity of peroxidase was stimulated under boron deficiency at all levels of calcium and that of ATPase was depressed significantly when calcium was deficient alone. A decrease in the tissue boron (except in old leaves) and tissue calcium content as well as sugar...

A Search for Extractants to Evaluate the Iron Status of Plants

An investigation was carried out to identify the fraction of Fe in maize tissues (Zea mays L. cv. Tipakhia) as an indicator of Fe supply in the rooting medium to distinguish plants which are deficient in Fe from those containing a sufficient amount of Fe. In plants grown at graded levels of Fe supply ranging from acute deficiency to excess, the content of Fe in fresh leaf tissues, extracted in 14 different extractants was estimated. The concentration of Fe in 5 of the extracts-using 1 N HCl, l N oxalic acid, 1 N citric acid, 0.1 N EDTA, and 0.1 N DTPA, was found to be positively correlated with the Fe supply in the medium. Critical Fe concentrations in plant tissues were determined using 1 N oxalic acid and 1 N HCl-extractable Fe fractions.

Manganese, zinc and boron deficiency in mango

Abstract Mango (Mangifera indica L.) cultivar ‘Dashehari’ was grown in refined sand in complete nutrition and at two levels which were deficient in Mn (0.0055 and 0.055 mg l−1), Zn (0.0013 and 0.0065 mg l−1) and B (0.0033 and 0.033 mg l−1). The visible symptoms of Zn deficiency appeared first, and those of B and Mn appeared later. In both Zn and Mn deficiency, the young and middle leaves were affected but the symptoms were entirely distinct from each other. The symptoms of B deficiency were first visible on the young leaves, then the apical growing point died and subsequently a large number of the secondary buds died. The levels of Mn, Zn and B were reduced in the leaves of deficient plants and decreased with increasing severity of the symptoms. After 124 weeks, leaf Mn was 3.8 μg, Zn was

Iron‐manganese‐magnesium interaction in cauliflower

Abstract Cauliflower (Brassica oleracea L. var. Botrytis) was grown in refined sand in complete nutrient solution and in solutions deficient each in Fe (0.56 ppm), Mn (0.0055 ppm), Mg (0.5 ppm), Fe‐Mn, Fe‐Mg, Pln‐Mg and Fe‐Mn‐Ng. The magnitude of depression owing to Fe deficiency in dry matter, leaf iron, chlorophyll, starch, protein, RNA and the specific activities of catalase and peroxidase was mitigated, to variable extent, by the combined deficiencies of Fe‐Mg, Fe‐Mn and Fe‐Mn‐Mg. The depression in aldolase. activity in iron deficiency became more pronounced by the combined deficiency of Fe‐Mn and Fe‐Mn‐Mg. Hill activity per mg chlorophyll was least in Mn deficiency, its activity and those of Mg‐ATPase and RNAse uhich were enhanced by Fe deficiency alone, were depressed by the combined deficiencies of Fe‐Mn, Fe‐Mg and Fe‐Mn‐Mg. In the latter two treatments and in Mg deficiency, the pyruvate kinase activity was also depressed.

Boron nutrition of cowpea

Cowpea (Vigna sinensis L.) cv. Rituraj was grown in refined sand at graded levels of boron ranging from 0·0033 to 6·6 mg l−1. Maximum biomass and seed weight were obtained at 0·33 mg B l−1 supply. In acute deficiency of boron (0·0033 and 0·033 mg l−1), its deficiency symptoms were pronounced, the biomass was depressed markedly and neither pods nor seeds were formed. At moderate deficiency of boron, deficiency symptoms were mild and the number and weight of seeds were reduced by about 40% and 50% respectively. Marked boron toxicity symptoms were observed at 6·6 mg B l−1 supply where not only biomass and seed yield but also the concentration of starch and non-reducing sugars and the activity of starch phosphorylase and ribonuclease were depressed. In the latter treatment reducing sugars were increased so also the activity of polyphenol oxidase and peroxidase. In acute boron deficiency, the concentration of reducing sugars and non-reducing sugars were increased so also the activity of peroxidase, ribonuclease and polyphenol oxidase but the activity of starch phosphorylase was depressed only at 0·0033 mg B l−1 supply. As the concentration of boron in seeds was markedly less than in leaves, the values of deficiency, threshold of deficiency and threshold of toxicity in leaves was higher than in seeds.

Excess Sulphur Partially Alleviates Copper Deficiency Effects in Mustard

Abstract Mustard (Brassica campestris L. var. sarson) cv. T42 was grown in refined sand at two copper levels, deficient (10−8 M) and normal (10−6 M), each at two molybdenum levels, normal (5×10−7 M) and excess (10−4 M), and two levels of sulphur, normal (2 × 10−3 M) and excess (4 × 10−3 M) with nitrate and ammonium nitrate as nitrogen sources. In mustard, excess sulphur interacted with copper deficiency when the supply of excess sulphur at adequate molybdenum levels partially alleviated the effects of copper deficiency namely, visible copper deficiency symptoms, decrease of dry weight, seed yield and the activity of cytochrome oxidase. The alleviation of copper deficiency effects by excess sulphur was also discernible at excess molybdenum levels. Excess S interacted with excess Mo in decreasing significantly the tissue Mo contents for both nitrogen sources. Excess S also significantly depressed the NR activity in the NO3 treatment at both levels of Mo supply, indicating the presence of an interaction betw...