Application Of Maleic Hydrazide Research Articles

Combination of maleic hydrazide and coumarin inhibits rice seed germination involving reactive oxygen species accumulation, ABA metabolism and starch degradation

Pre-harvest sprouting (PHS) in cereal crops is a prevalent phenomenon that impacts grain yield and quality. Several PHS inhibitory compounds were screened and identified in previous studies, such as eugenol (EUG), maleic hydrazide (MH), coumarin (COU), etc. However, few studies have focused on the combination of PHS inhibitors, and the inhibitory mechanism remains unclear. Here, through combination tests of EUG, MH, and COU, the optimal combination of PHS inhibitors was selected as MH 20 mg L−1 + COU 100 mg L−1, which presented the lowest germination percentages. The optimal combination treatment significantly decreased the germination rate, α-amylase activity, content of soluble sugar and soluble protein, enhanced ABA content and the activity of superoxide dismutase (SOD) and peroxidase (POD), inhibited the production of superoxide anion (O2−) and hydrogen peroxide, and reduced the content of malondialdehyde (MDA); conversely, this trend is precisely the opposite in normal germination. Furthermore, gene expression analysis revealed that the optimal combination of MH and COU significantly decreased the expression level of OsAmy1A and OsAmy3D at 12 and 48 h after imbibition (HAI); and promoted the expression of OsRbohs (OsRbohA, OsRbohC, OsRbohD, OsRbohE, OsRbohH) and ABA biosynthetic genes OsNCED1, OsNCED2, and OsNCED5, especially OsNCED2 at 12 HAI, but down-regulated expression of OsRbohs and ABA catabolic genes OsABA8ox1-3 at 48 HAI. These results demonstrated that the delay in seed germination induced by MH and COU involved in ROS, ABA, and sugars; the optimal combination of MH and COU inhibited the germination process by promoting ABA biosynthesis and reducing ABA catabolism, and restraining the α-amylase activity to lower soluble sugar content. Intriguingly, although the expression of OsRbohs, which play a crucial role in generating ROS, increased in early imbibition (12h), the activity of the antioxidant enzymes SOD and POD also increased with the optimal combination treatment of MH and COU, which lead to the delay in ROS accumulation and inhibition of germination. These results have deepened our understanding of the regulatory mechanism of PHS inhibitors and provided theoretical support for the application of MH and COU in preventing sprouting before crop harvesting.

Assessing the Synergistic Effects of Deficit Irrigation and Growth Retardants on Insitu Sprouting and Quality Parameters of Groundnut VRI 8

Background: Groundnut is a crucial oilseed crop cultivated year-round, with seed dormancy controlled by genetic and environmental factors. Preventing pre-harvest sprouting is essential, as it is a common issue. To study the effect of deficit irrigation management and foliar application of growth retardant chemicals on pre-harvest sprouting control efficiency to achieve higher yield of groundnut. Methodology: In a field experiment conducted during early summer 2024 at the Agricultural College and Research Institute, Madurai, the effectiveness of different growth retardant chemicals and deficit irrigation management on reducing in-situ sprouting of groundnut kernels was investigated. The experiment included three irrigation management strategies: conventional irrigation and two deficit irrigation treatments where irrigation was withheld from 90 to 105 DAS (Days After Sowing) and 85 to 100 DAS. Additionally, foliar sprays of growth retardant chemicals were applied at 75 and 90 DAS. The chemicals tested were maleic hydrazide (MH) @ 1250 ppm, cycocel (CCC) @ 1000 ppm, abscisic acid (ABA) @ 750 ppm, and salicylic acid (SA) @ 750 ppm. Proper agronomic practices were followed throughout the crop growth cycle. Results: Among the growth retardant chemicals tested, MH @ 1250 ppm proved effective in inducing dormancy. Withdrawal of irrigation from 90 to 105 DAS also significantly contributed to dormancy induction, extending dormancy by more than 5 days post-harvest as well as reduced the pod loss which significantly increased pod yield. It was because of the reduction in soil moisture content during harvest stage and alteration in the hormonal activities. Specifically, the combined treatment of foliar application of MH @ 1250 ppm and no irrigation from 90 to 105 DAS reduced germination percentage by 12.6%, 36.8% and 60.5% immediately 5, 10 and 15 days after harvest respectively. Conclusion: The reduction in soil moisture content during the harvest stage, coupled with changes in hormonal activities, significantly impacts seed sprouting. These factors can lead to stress conditions that hinder germination, ultimately affecting crop yields. Addressing these issues is crucial for ensuring optimal seed development and enhancing agricultural productivity.

Influence of plant growth regulators on vegetative growth, sex expression and yield of summer bottle gourd

Field experiments on bottle gourd variety ‘BARI Lau -4’ were conducted at the Plant Physiology field of Horticulture Research Center, Bangladesh Agricultural Research Institute, Gazipur during two consecutive summer seasons of 2015 and 2016 to investigate the effect of plant growth regulators on growth, sex expression, yield and yield components of the crop. The experiment consisted of different concentrations of Gibberellic acid (GA3), Naphthalene acetic acid (NAA), Maleic hydrazide (MH) and single concentration of cycocel (CCC) viz., GA3 @ 10 ppm, GA3 @ 30 ppm, NAA @100 ppm, NAA @ 150 ppm, MH @ 50 ppm, MH @ 150 ppm and CCC @ 500 ppm along with distilled water considered as control. All growth regulators were sprayed to the seedlings at two-leaf stage and 4 days after the first spray. Growth regulator treatments had significant effect on primary branches/plant, node number of 1st male and female flower appearance, number of days to 1st male and female flower appearance, number of male and female flowers, sex ratio (male:female flower) number of fruits/plant, individual fruit weight and fruit yield. Spraying of MH @ 150 ppm gave the highest primary branches/plant (17.0 and 18.0 in first and 2nd year, respectively) and induced maximum female flowers (37.3 and 40.0 in first and 2nd year, respectively) at lower nodes followed by CCC @ 500 ppm (36.3) in the first year and MH @ 50 ppm (40.0) in the 2nd year. Application of MH @ 150 ppm caused early appearance of female flowers on the nearest node (from bottom). Application of MH @ 150 ppm gave the lower number of male flowers (81.7 and 96.0 in first and 2nd year, respectively) and the highest number of female flowers/plant, thereby producing lower male:female sex ratio (2.2 and 2.5 in first and 2nd year, respectively) and the maximum number of fruits/plant (12.0 and 14.0 in first and 2nd year, respectively). The maximum fruit weight/plant was obtained from the application of MH @ 150 ppm (29.3 and 35.8 in first and 2nd year, respectively) followed by CCC @ 500 ppm (26.0 in the 1st year and 29.0 in 2nd year). The highest fruit yield per hectare was recorded significantly with the application of MH @ 150 ppm (97.6 t/ha and 89.6 t/ha in first and 2nd year, respectively) closely followed by CCC @ 500 ppm (88.5 t/ha in 2015) and GA3 @ 30 ppm (75.3 t/ha in 2016), as compared to other treatments. The highest mean yield over the years was also recorded at MH @ 150 ppm (93.6 t/ha) followed by CCC @ 150 ppm (80.6 t/ha) and GA3 30 (74.1). Application of MH @ 150 ppm gave the maximum gross return and net return with the highest BCR of 5.24 followed by CCC 500 ppm (4.15) and GA3 30 ppm (3.86).
 Bangladesh J. Agril. Res. 44(4): 577-590, December 2019

Soil Applied Maleic Hydrazide Does Not Suppress Tobacco Axillary Bud Growth

Core Ideas Maleic hydrazide residues are a threat to the US tobacco industry. Alternative application methods could prove beneficial. Root absorption of maleic hydrazide appears to be limited. With an increasing focus on maleic hydrazide (MH) residues and the need to sufficiently control axillary bud (sucker) growth, flue‐cured tobacco (Nicotiana tabacum L.) producers would benefit from an alternative to the conventional foliar application method of the plant growth regulator. Research was conducted in four North Carolina environments from 2014 to 2015 to quantify the efficacy of soil applications of MH. Two rates of MH were selected (2.25 and 4.50 lb a.i./acre) and were applied in combination with one of three sucker control programs: foliar MH preceded by foliar flumetralin (F treatment), soil MH preceded by foliar flumetralin (SF treatment), or soil MH preceded by foliar fatty alcohol (SFA treatment). Ranging from 95 to 100%, sucker suppression was greatest in F treatments. In two Coastal Plain environments, the control in SF treatments was similar to that of F treatments; however, in the two Piedmont environments, the control was reduced by 30 to 50%. Sucker suppression was lowest in SFA treatments, particularly in the Piedmont environments, thus indicating that flumetralin was the likely source of suppression in SF treatments. No differences were observed between the two MH application rates evaluated. Given the observations of this study, it is unlikely that a soil application of MH will serve as an effective sucker control alternative to the standard foliar application used at present by commercial growers.

Effect of growth retardants on growth and flowering of bougainvillea (Bougainvillea spectabilis) cv. Shubra

The present investigation to study the effect of growth regulators on growth and flowering of bougainvillea (Bougainvillea spectabilis) was carried out in the Division of Floriculture and Landscaping, IARI, New Delhi during 2012-13. The experiment was laid out in completely randomized block design with 11 treatments, 4 replications and 4 plants per replication. The bougainvilleas were planted in 10 inches pots in the month of July and were pruned back to a uniform height of 10+2 inches. The growth regulators, viz. maleic hydrazide, B-9 and paclobutrazol were applied in the form of foliar spray or drench and were compared with control (Distilled water) and the data were recorded for vegetative and flowering traits. Over a period of 14 weeks, it was observed that there was a significant reduction in plant height, plant spread, internode distance and shoot length with the application of maleic hydrazide followed by drenching with paclobutrazol. Maximum shoot diameter, maximum number of structural branches and maximum flower index was observed when plants were either sprayed or drenched with paclobutrazol.

Inhibition of spinach bolting by growth regulators

Spinach (<i>Spinacia oleracea</i> L.) plants must be harvested during a short period of time because they bolt just after producing some edible leaves. Maleic hydrazide (MH) and its commercial preparation "Antyrost" were found to inhibit bolting very strongly. The preparation Off-shoot-O showed very weak activity in suppressing bolting but diminished markedly the resistance of spinach plants to fungus diseases. Triiodobenzoic acid stimulated bolting, and the retardant succinic acid-2-2-dimethylhydrazide (SADH) did not affect bolting. Application of MH to inhibit spinach bolting cannot be recommended in practice before investigating the residues of this compound in leaves.

Anticlastogenic effect of S pirulina maxima extract on the micronuclei induced by maleic hydrazide in Tradescantia

The aim of this investigation was to determine if extracts of Spirulina maxima reduce the genotoxic damage induced by maleic hydrazide (MH) using the Tradescantia biosssay. Two types of extracts from the alga were prepared: an aqueous extract with two different concentrations, 100 and 500 mg/ml, and a second one, the extract of a 1% solution of dimethyl sulfoxide (DMSO) which corresponded to 100 mg/ml of the alga. The capacity of MH to induce micronuclei (MN) was initially established by administering 0.005, 0.01, and 0.015 mg/ml of the chemical to the Tradescantia inflorescences, and observing its effect after 24 h. The results of this experiment showed a significant MN increase with the two high concentrations tested, although no dose-response effect was observed. For the anticlastogenic assay, the extracts of Spirulina were applied to the inflorescences alone or immediately before the application of MH (0.01 mg/ml) and the induced MN were observed 24 h later. We found that none of the extracts increased the MN level with respect to the untreated plants; also, that MH more or less doubled the basal micronuclei frequency, and finally, that all tested extracts reduced the genotoxic damage caused by MH. The inhibitory indices obtained for the aqueous extracts (100 and 500 mg/ml) and for the DMSO extract were respectively 59, 85, and 56.3%. These data indicate that Spirulina is an anticlastogenic agent and suggest that it is advisable to extend studies on this matter using other biological models.

Effects of Plant Growth Regulators and their Time of Application on Flower Bud Formation of Japanese Pear 'Kosui'.

Effects of several plant growth regulators on flower bud initiation on current shoots in Japanese pear (Pyrus pyrifolia Nakai) cv. Kosui were investigated. The applications of maleic hydrazide (C-MH, 1, 2-dihydro-3, 6-pyridazinedione choline) ; uniconazole-P (UCZ, (E)-(S)-1-(4-chlorophenyl)-4, 4-dimethyl-2-(1H-1, 2, 4-triazol-1-yl) pent-1-en-3-ol) ; benzylaminopurine (BA, N-(phenylmethyl)-1H-purin-6-amine) ; and abscisic acid (ABA) from early June to early August promoted flower bud formation or were ineffective depending on the time of application. C-MH increased flower bud number when applied in July, whereas UCZ was effective only when applied before or in early July. BA and ABA applications increased flower bud number when applied between early June and late July. The effect of gibberellin (GA4) application differed depending on the application date. Compared to the control, fewer flower buds were initiated by early June application ; whereas more were formed by an early August spray. The possible mechanism (s) on how these regulators affect flower bud initiation on shoots of Japanese pear 'Kosui' are discussed.

The influence of incorporated bromodeoxyuridine on mutagenicity testing by sister chromatid exchange induction inVicia faba root tip cells

The induction of sister chromatid exchanges (SCEs) inVicia faba root-tip cells after short-term (2 h) and long-term (24 h) treatments with alkylating agents (N-methyl-N-nitrosourea, ethyl methanesulphonate) and maleic hydrazide was studied. The primary roots were treated with mutagens before or after 5-bromodeoxyuridine (BrdU) incorporation into DNA and the influence of mutagen application on SCE induction in the cells with non- and BrdU-substituted chromosomal DNA. On the contrary, application of maleic hydrazide after the incorporation of BrdU into DNA strongly increased the rate of SCEs. The lowest limit concentrations of mutagens capable of significantly increasing SCE frequency in the cells with non-substituted DNA after the long-term treatment were estimated.

Nitrate Assimilation in Tobacco Leaves Treated with Maleic Hydrazide to Control Axillary Bud Growth

After removal of the upper stalk containing the developing inflorescence and small expanding leaves (<20 cm) of hurley tobacco (Nicotiana tabacum L.), maleic hydrazide (MH) is used to control axillary bud growth (suckers) and enhance economic yield. Maleic hydrazide has numerous physiological effects on tobacco; many represent delayed or secondary effects on plant metabolism and may affect chemical composition of leaves. The effects of MH level (0, 0.17, 0.34, and 0.68 g plant −1) on the in situ assimilation of nitrate and other selected physiological traits of the second leaf from the top in plants grown in 1989 and 1990 were determined at weekly intervals for 3 wk beginning ⊄10 d after the MH application. Total chlorophyll in laminal tissue decreased as MH level increased; this response to MH became increasingly pronounced with time. The dry weight of the second leaf from the top increased with time, but differences in leaf weight due to treatment were not significant. Leaf total N and nitrate concentrations of the lamina averaged across both years and three sampling dates decreased with increasing MH level. However, in situ assimilation of nitrate was unaffected by MH. Differences in leaf N concentrations due to MH are partly the consequence of greater leaf dry weight accumulation and possibly to decreased uptake and partitioning of nitrate rather than nitrate assimilation. The slightly lower levels of nitrate in the upper leaves of MH‐treated burley tobacco should be a desirable benefit of chemical suppression of suckers, because lower levels of tissue nitrate are often associated with decreased production of nitrosamines in cigarette smoke.

Effect of maleic hydrazide on photosynthesis, carbohydrate metabolism, and senescence of burley tobacco (Nicotiana tabacum L.)

Maleic hydrazide (MH), a systematic agent used for control of axillary growth (suckers) in tobacco production, has been shown to alter cured-leaf quality and increase yield compared to manual sucker control. The objective of this study was to determine how MH, applied at rates ranging from zero (manual sucker control) to four times the usual commercial rate of 3.36 kg ha−1, influenced the carbon dioxide exchange rate (CER), carbohydrate metabolism, and senescence of upper-canopy leaves. Leaves treated with various MH rates had residue levels ranging from zero to over 600 μg g−1. Leaf area was decreased and specific leaf weight was increased by increasing MH rates. Oven-dried leaf weight, however, was similar for all treatments. CER was markedly decreased 2 weeks after applying MH rates above 1.68 kg ha−1. Chlorophyll concentration was also decreased by MH application, but not as rapidly or to the same extent as observed for CER. Sucrose and starch levels were significantly increased within 2 weeks after applying MH. As with CER, MH effects on sucrose and starch accumulation were maximum at 3.36 kg ha−1 MH with no further change at higher rates. Activities of sucrose-phosphate synthase (SPS) and adenosine diphosphate glucose (ADPG) pyrophosphorylase were not affected by any MH treatment. The results indicated that the increased sucrose and starch accumulation was due to decreased translocation of assimilate and not to increased photosynthesis. Because MH did not markedly alter total plant dry matter accumulation, MH-induced decreases in CER and chlorophyll were possibly compensated for by leaves lower in the canopy. This conclusion was supported by the lack of effect of MH on starch and sucrose accumulation and chlorophyll concentration of leaves in the middle of the canopy. While MH did inhibit photosynthesis of upper-canopy leaves, the results indicated that, in general, plant senescence was not markedly affected.

Combined application of MH and TEM for conditioning treatment simultaneously triggers two protective functions against induction of chromatid aberrations in Vicia faba root tip meristem cells

Conditioning pre-exposure of Vicia faba root tip meristem cells to triethylenemelamine (TEM) does not trigger an adaptive response to maleic hydrazide (MH) and vice versa. Since TEM conditioning treatment can induce protective effects (as evident from the yield of metaphases with chromatid aberrations) against TEM challenging treatment and MH conditioning can trigger an adaptive response to MH challenging treatment, two different protective functions are apparently triggered in dependence on the agent used for conditioning pre-exposure. When a mixture of TEM and MH is being used for conditioning treatment, adaptive responses to both TEM and MH can simultaneously be induced and significantly reduce the yield of metaphases with chromatid aberrations observed after challenge treatment with TEM or MH.

昼夜温がトウガラシ属のつぼみおよび花の脱離に及ぼす影響

Effect of day/night temperature on bud and flower abscission in pepper (Capsicum annuum L.) was studied using four varieties, ‘New Ace, ’ ‘Fushimi Amanaga, ’ ‘Thai Chilli’ and ‘Oriental Glory.’ Plants were grown in phytotrons with day/night temperatures 37/27, 32/22, 27/17°C under natural day light. Bud-abscission percentage increased with increasing the temperature especially in Thai Chilli, while no apparent relationship between temperature and flowerabscission percentage was observed, indicating flower buds were susceptible to high temperature. Also, the effect of different night temperatures (27, 22, 17°C with a constant day temperature of 37°C) and different day temperatures (37, 32, 27°C with a constant night temperature of 22°C) on bud and flower abscission of Thai Chilli was investigated, individually. In the former experiment, night temperature was found to have effect on only flower-abscission percentage. In the latter experiment, bud-abscission percentage increased with increasing day temperature.The effect of two plant growth regulators on bud and flower abscission were examined using the var. New Ace and Thai Chilli under two day/night temperatures (37/27 and 27/17°C) . Application of maleic hydrazide (MH) and silver thiosulfate (STS) did not affect bud and flower abscission in New Ace. Mean while, application of vegetative growth inhibitor, MH, affected flower abscission in Thai Chilli.These results indicate that, bud and flower abscission of peppers under high temperature might be caused by a hormonal mechanism, a failure in fertilization of the flower and competition for assimilates between bud and young leaves. Low night temperature and application of plant growth regulators might have an effect on the competition for assimilates, resulting in bud and flower abscission.

Growth Regulators' Effect on Crested Wheatgrass Forage Yield and Quality

If crested wheatgrass [Agropyron desertorum (Fisch.) Schult.] could be maintained in an immature growth stage, it would improve forage quality and thus extend the grazing season. In 1981 and 1982, plant growth regulators were applied to crested wheatgrass 0, 2, 4, and 6 weeks after first floral primordium initiation to determine which compound, date, and rate of application would maximize forage quality yet minimize reduction of forage yield when harvested at seed ripe stage. Mefluidide [N-(2,4-dimethyl-5{[(trifluoromethyl)-sulfonyllamino}phenyl)acetamidel at 4 rates [0.0, 0.28, 0.56, and 0.84 kg/ha active ingredient (a.i.)], maleic hydrazide (MH) (1,2-dihydro-3,6-pyridazinedione) at 4.5 kg/ha ai., and MH (3.36 kg/ha ai.) phl chlorflurenol (methyl-2-chloro-9-hydroxyfluorene-9-carboxylate) at 1.12 kg/ha a.i. were applied to crested wheatgrass growing on a Shambo loam (Typic Haploborolls) in northeast Montana. Application of MH or MH plus chlorflurenol generally gave a similar response in heading, forage yield, CP, and in vitro organic matter digestibility on a dry matter basis (IVDOMD) as did melfluidide at 0.56 kg/ha. Mefluidide (0.56 kg/ha) applied 2 weeks after first floral primordium initiation decreased heading 80 and 95%, decreased forage yield 20 and 30%, increased CP 1.7 and 2.3 percentage units, and increased IVDOMD 1.8 to 4.2 percentage units compared to untreated, depending upon

Maleic Hydrazide Effects on Soybean Reproductive Development and Yield1

AbstractDrift or misapplication of maleic hydrazide (MH) to tobacco (Nicotiana tabacum L.) sometimes effects neighboring soybean [Glycine max (L.) Merr.] fields. Our objective was to determine the effects of various rates and timings of MH application on soybean reproductive development and yield. Applications of 0.34 to 3.4 kg a.i. ha−1 were applied to soybean during the R3 to R6 growth stages. Significant (P<0.05) yield reductions from 30 to 100% occured when even low rates of MH were applied to soybean at growth stages R3 and R4. Yield losses occurred primarily as a result of decreased numbers of pods per plant. Injured soybean plants remained green until killing frosts. Plants treated with MH at the R5 and R6 stages experienced no yield loss and matured normally. Planting shorter‐season soybean cultivars early could result in soybean being past the sensitive stages when MH is applied, resulting in little or no injury if misapplication or drift occurs.

Response of American sycamore seedlings to maleic hydrazide and sodium chloride

AbstractAmerican sycamore (Platanus occidentals L.) seedlings grown in a hydroponics system were treated with a growth regulator, maleic hydrazide (MH) or sodium chloride, or a combination of the two. Application of maleic hydrazide or sodium chloride retarded plant growth, but combined application did not show significant interaction effects. Treatment with both sodium chloride and MH reduced the dry weight of plant tissue to a greater extent than sodium chloride application alone. Elemental analyses of various plant parts revealed that MH was generally without effect on the level of either sodium or chloride ions. In old stem tissue, however, treatment with MH had no effect in the absence of sodium chloride but was associated with lower chloride content in its presence.

Effect of Sprout Inhibitors and Nitrogen Fertilization on Nitrate‐N Content of Potato Tubers

ABSTRACTThe effect of sprout inhibitors, maleic hydrazide (MH), and isopropyl‐N‐(3‐chlorophenyl)‐carbamate (CIPC), on nitiate‐N (NO3‐N) content of tubers was investigated. The effect of rate of application of nitrogen fertilizer and variety on NO3‐N content of tubers was also examined. Foliar application of MH significantly (p < 0.01) increased NO3‐N content of the tubers. NO3‐N content increased significantly (p < 0.01) with increasing amounts of MH application. No significant differences in NO3‐N content of tubers were observed with CIPC treatment. NO3‐N content increased significantly (p < 0.05) in tubers with increasing nitrogen fertilization rates. Varieties differed in their NO3‐N content. The NO3‐N content of the cortex was significantly (p < 0.05) higher than the corresponding pith tissue regardless of treatment.

Factors influencing incidence of internal brown spot in Russet Burbank potatoes

Studies were conducted to determine factors influencing incidence of internal brown spot (IBS) in Russet Burbank potatoes. A significant decrease in the incidence of IBS occurred as planting date was delayed from March 31 to May 12. IBS increased during storage particularly at the higher storage temperature and in larger tubers. Foliar application of maleic hydrazide (MH) significantly reduced IBS from a high of 33% of tubers to less than 10%. The incidence of IBS in tubers was lower in the field as well as in storage from plants sprayed with MH. Tubers with high specific gravity had greater incidence of IBS than low gravity tubers. Results indicate that IBS is a physiological disorder influenced by factors affecting growth of tubers.

Effect of two forms of maleic hydrazide on the cell structure at the midsection, stem and bud ends of the cortical and perimedullary regions of Russet Burbank tubers

The cortical and perimedullary cells of the potato tuber increased in size when treated with the diethanolamine and the potassium salt of maleic hydrazide. The best time for maleic hydrazide application appeared to be from mid to late July. There was a greater increase in cell size in the cortex than the perimedullary region and treatment with the amine salt was more effective than the potassium salt. The cells were smallest at the bud end; however, with maleic hydrazide treatment, increase in cell size was greater in this region compared to the midsection and stem end. From late August to late September the cell size of untreated tubers remained relatively unchanged, whereas, tubers treated with the amine salt showed a 16 to 46% increase with a lesser increase with the potassium salt. The rounder form of the treated tubers can be explained by the shape and increase in cell size in the cortical and perimedullary region. Increase in cell size also may help prevent the formation of misshapen tubers.

Use of Growth Regulators for Increased Quality of New Zealand Spinach1

Abstract Repression of specific growth parameters of Tetragonia tetragonioides (Pall.) Kuntze (syn. Tetragonia expansa Murray) was studied after application of two types of growth regulators. Succinic acid-2,2-dimethylhydrazide (SADH) decreased stem height and dry weight progressively with increased concentration. Ratio of leaf dry weight to stem dry weight increased with concentration. Maleic hydrazide (MH) caused substantial reduction of fruit weight, with fruit number decreasing only at higher concentrations. Whole plant fresh weight and leaf area decreased only with a multiple 500 ppm application of MH. Leaf to fruit fresh weight ratio increased with concentration and number of applications. A formulation C6 to C12 fatty alcohols (Off-Shoot T) had little effect on fruit development and leaf area.