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  • Author or Editor: B. Esther Struckmeyer x
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Abstract

Succinic acid 2,2-dimethyl hydrazide (Alar) was applied as 3 weekly foliar sprays at concentrations of 0, 1000, and 2000 ppm to ‘Sovereign’, an Fj cultivar of Tagetes erecta L., grown in a complete nutrient supply under long and short day photoperiods. Plants were sampled for anatomical study one week later. Treated plants grown under long days had thicker leaves and a larger root diameter. In short days, the capitula of treated plants were one-half the size of the untreated ones. The amount of phloem fibers in treated plants was less and cortical and pith cells were shorter in both photoperiods. Alar affected cell wall formation and the phloem fibers in the stems were thinner walled and less sclerified.

Open Access

Abstract

An anatomical comparison of florets from fertile, brown anther partially fertile, petaloid male-sterile, and 3 brown anther male-sterile carrot (Daucus carota L.) lines indicated that most pollen was well-developed and deeply stained in fertile lines. Partially fertile plants contained fertile and sterile anthers in which meiosis had occurred. The 3 lines of brown anther steriles examined failed to enter meiosis. In early development of the fine foliage brown anther sterile, all cells of the anther, including sporogenous cells, hypertrophied. Later, sporogenous tissue collapsed. The anatomical structure of the stamens in petaloid florets was leaf-like and similar to petals.

Open Access

Abstract

Succinic acid 2, 2-dimethylhydrazide (Alar) was applied as a foliar spray to ‘Sovereign’, an F1 cultivar of Tagetes erecta L., grown in a complete nutrient solution. Alar was applied weekly as a foliar spray at concn of 500, 1000, and 2000 ppm to plants grown under both short and long days. Short day control plants were shorter, flowered earlier, and had shorter leaves than the long day control plants. In each photoperiod, all plants treated with Alar were significantly shorter than the controls because of shorter in tern odes. Dry wt of the tops of treated plants were significantly less than the controls, but the dry wt of the roots were not significantly different. Leaf length and no. of nodes were not affected by the different concn. In short days, Alar delayed flowering up to 8 days, but did not affect the size of the terminal flower.

Open Access

Abstract

Pollen of onion (Allium cepa L.) was stored in incubators at 21, 43 and 60°C with each at 20, 50 and 80% relative humidity. The germination of M611B pollen was higher than P52-371B. At each of the temperature levels, germination of viable pollen decreased as the relative humidity and length of storage time increased. Increasing temperature also caused an increase in nonviable pollen. At 21°C, pollen germination showed a gradual decline with increasing length of storage compared to a more abrupt decline at 43 and 60°C.

Open Access

Abstract

Male fertile lines M611B and P52-371B and male-sterile lines M2399A and P54-306A of onion were grown in 3 chambers in the Biotron with maximum temperatures of 24°C, 35°, and 43° and a minimum of 18°. Temperature and flower age affected longevity and viability of pollen. There was no striking difference in % germination between the 2 male-fertile lines in time of day pollen was collected from flowers of the same age. At 24° stigma receptivity was highest on the 4th day; at 35°, the 3rd day; and at 43°, the 1st day after anthesis. Pollen started germinating ½ hour after placement on the stigma at the 3 temperatures. Pollen tubes grew the entire length of the style within 12 hours after pollination. The highest % fruit set was at 35°. Seeds per ovary were 2.57, 3.20 and 1.66 for 24°, 35° and 43°, respectively.

Open Access

Abstract

Male-sterile onion lines, M2399A and P54-306A were hand pollinated with pollen from 2 male-fertile lines M611B and P52-371B, in 3 Biotron chambers with maxima temperatures of 24°, 35°, and 43°C, respectively, and a minimum temperature of 18°C. There was no significant effect of temperature on magagmetophyte development. Percent abortion of young seeds was 21, 11, and 66% at 24°, 35°, and 43°, respectively; 35° was more favorable for ovule, seed and ovary growth than 24° and 43°. The endosperm nuclei divided soon after fertilization and continued normally the first 5 days after pollination at all 3 temperatures. Subsequent growth of endosperm nuclei was retarded at 43° and only 1 or 2 seeds per ovary continued to grow at a normal rate. The first embryo division was observed 7 to 8, 5 to 6, and 6 to 7 days after pollination at 24°, 35°, and 43°, respectively.

Open Access

Abstract

Powdery mildew susceptible ‘Chipper’ cucumber (Cucumis sativus L.) plants grown with slight, moderate, or severe N, P, K, Ca, Mg, and S stress had higher element concentrations than resistant ‘Natsufuchinari’ plants although cultivar differences were not significant. One week after host inoculation, colonies of powdery mildew (Erysiphe cichoracearum D.C.) were smaller and had fewer conidiophores on resistant than on susceptible plants. Plants grown with slight or moderate nutrient stresses usually had larger colonies and more conidiophores than either controls or severely stressed plants. N and Ca stressed plants had lower N and Ca concentrations and smaller colonies with fewer conidiophores than plants grown with other stress treatments.

Open Access

Abstract

Severe chlorosis of leaves and cellular disruption and distortion in the roots usually associated with Cu toxicity were absent from plants grown in solution culture with high Cu (0.50 ppm) to which succinic acid 2,2-dimethyl hydrazide (SADH) was added. The presence of either SADH or EDTA in the nutrient solutions increased the Fe concentration in the roots and shoots; a synergistic effect appeared when the compounds were combined. Plants grown with EDTA had lower Cu levels in the shoots and roots than those grown without EDTA. Although SADH alone had no effect on Cu concentrations, SADH and EDTA together, caused low concentrations in the roots regardless of the Cu level in the nutrient solution.

Open Access

Abstract

Transplants of cabbage (Brassica oleracea L. Capitata group) grown in growth chambers under continuous illumination of 310 μE m−2sm−1 (21.5 ± 1.1 klx) and temperature of 20 ± 1°C developed tipburn-like symptoms on young leaves within 8 to 14 days when maintained at 82% but not at 52% relative humidity (RH). Plants had larger leaves and greater fresh and dry weights at 82% than at 52% RH.

Open Access

Abstract

Clerodendrum thomsoniae Balf. plants untreated and treated with a 0.3 mg drench of ancymidol (a-cyclopropyl-a-(4-methoxyphenyl)-5-pyrimidmemethanol) flowered under a 12 hr photoperiod and were mostly vegetative under a 15 hr photoperiod. Initiation of flower parts was 8 days earlier in ancymidol treated than untreated plants. Although ancymidol hastened the initiation of flower parts, untreated plants flowered at nearly the same time as treated ones. The shoot apex remained vegetative and axillary buds flowered in treated and some untreated plants. In untreated plants, flower induction in the axillaries was apparent at 12 days and only sepal and petal primorida were present at 16 days after the initiation of the experiment when the plants were 9 cm tall. In treated plants, induction was apparent 4 days after treatment; flower development was accelerated; and at 16 days all flower parts were differentiating.

Open Access