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  • Author or Editor: D.J. Donnelly x
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Abstract

Isoenzyme analysis of leaf tissue was used to characterize and separate 18 greenhouse-grown red raspberry (Rubus idaeus L.) cultivars and two purple raspberry (R. ×neglectus Peck) cultivars. Five enzymes were found to be useful: Phosphoglu-coisomerase (PGI), phosphoglucomutase (PGM), malate dehydrogenase (MDH), triose phosphate isomerase (TPI), and isocitrate dehydrogenase (IDH). Fourteen of the 20 cultivars were uniquely separated using these enzymes. The remaining six were assigned to three different groups. Staining for additional isoenzymes may lead to the separation of cultivars within these groups. The effect of tissue type on isoenzyme banding patterns was determined by comparing different tissues from three cultivars. No differences were noted, except in the case of the enzyme PGM, for which differences in the relative densities of the bands were seen. For PGM, the best patterns were obtained from mature tissues (leaves, stems, or petioles). Three cultivars were micro-propagated from shoot tips in vitro and were subsequently analyzed by isoenzyme staining. The culture environment was not found to have any effect on isoenzyme phenotype. This result suggests that isoenzyme analysis can be used to identify raspberry cultivars grown in vitro.

Open Access

The effect of successive harvests on potato microtuber yield (fresh weight and number) and size distribution in stationary liquid cultures was evaluated in cultivars Norland, Bintje, and Shepody. Harvesting microtubers successively at both 33 and 65 days, compared with a single harvest at 65 days, increased the total number of microtubers but decreased the number of larger microtubers (>0.75 g). Selective removal of Shepody microtubers >8 mm (>0.5 g) at 33 days increased the combined total number of microtubers from both harvests, but decreased the number of very large microtubers (>1.5 g). Successive harvest had no effect on total fresh weight yield, but increased overall microtuber numbers and skewed the size distribution downwards.

Free access

Abstract

The leaf anatomy of an aseptically cultured red raspberry clone (Rubus idaeus L.) was studied before and after transfer to soil under controlled environmental conditions. Leaves of plantlets formed in culture were smaller, thinner, had a less compact arrangement of palisade and mesophyll cells, and an altered palisade cell shape compared to leaves formed on plants in soil. The number of epidermal hairs, especialy the filiform type, was lower in vitro and the distribution of colleters was affected. Trichome number was greater in new leaves formed after transplantation and greatest in greenhouse- and field-grown control plant leaves. Calcium oxalate crystals were present in the leaves of in vitro plantlets and more numerous in the leaves formed on plants in soil. Stomata were fixed open, slightly raised, and occurred on the upper leaf surface of in vitro plantlets with many on the periphery of the leaf. Amphistomatous and the peripheral stomatal condition persisted in new leaves formed during the first month when cultured plantlets were transferred to soil at 3 or 6 klx. However, new leaves, like all greenhouse and field-control plant leaves, had few adaxial stomata at 9 klx and peripheral leaf stomata were rare. Anatomy of new leaves formed during the first month after transplanting in soil at 3, 6, or 9 klx was similar to those in culture. Parenchyma tissue was less compact than in control plant leaves and palisade cell shape remained abnormal. More than half the leaves from culture died within the first month of transferring plantlets to soil. Some survived for almost 3 months. Reduced trichome numbers, almost complete lack of filiform trichomes, and presence of peripheral and adaxial as well as unprotected, open, abaxial stomata would all contribute to transplant shock and water loss in cultured plantlets transferred to soil. New leaves of transplants, formed during the first month in soil, had transitional leaf anatomy and surface features. With time, in the soil environment, the appearance of subsequently formed leaves approached that of controls.

Open Access

Abstract

CO2 uptake and various leaf parameters were examined including photosynthetic pigment content (chlorophyll a, b, and total carotenoids), fresh/dry weight, percentage of water content, gram dry weight/area, and total plantlet leaf areas of an aseptically cultured clone of red raspberry (Rubus idaeus L.) incubated at 5 light intensities, from 2 to 6 klx. Cultured plantlets demonstrated relatively low levels of CO2 uptake, averaging 2.5 mg CO2 dm–2hr–1 and rarely exceeding 4 mg CO2 dm–2 hr–1 at saturating light intensities. Pigment content was higher in plantlets incubated at lower light intensities (2 to 4 klx). Cultures incubated at 3 klx were evaluated both at the time of transfer to soil and 1 month later. Plantlet leaves retained from culture could be distinguished from new leaves by tagging all plantlet leaves prior to soil transfer; both were assessed separately 1 month after transplantation. Leaves retained from culture, 30% of the total leaf area of transplants, contributed less than 10% of the CO2 uptake at 3 klx. These leaves accounted for 10% to 30% of the total leaf area at higher light intensities but were net respirers. There was an increase in dry matter accumulation at 6 and 9 klx in these tagged leaves, but not at 3 klx. Continued accumulation of dry matter by the tagged leaves can be only at the expense of photosynthetic activity of the newly formed leaves. New leaves of transplants had a greater dry matter accumulation at 9 klx and a pigment content greater than the tagged leaves. Their pigment content was similar to that of young, control plant leaves. Transplants were capable of uptake rates of 5–7 mg CO2 dm–2 hr–1 or 50% of field control rates. The photosynthetic contribution of the leaves from culture was small or negative. The first new leaves formed in soil were transitional with intermediate capability. Acclimatization to the soil environment was time dependent and required the production of new leaves initiated in the new environment.

Open Access

Abstract

Foliar anatomical comparisons were made between in vitro-grown plantlets and greenhouse-grown plants of ‘Queen Elizabeth’ rose (Rosa sp.) using scanning and light microscopy. Each acuminate leaf apex and marginal serration had a terminal hydathode region composed of a glandular tip and a subterminal, adaxial group of sunken water pores. Leaf apices of greenhouse-grown plants had up to 35 water pores per hydathode, while cultured plantlets had < 20. Hydathodes of leaf serrations had up to 10 water pores in both sample groups. Water pores and stomata of plantlet leaves were open, while those of greenhouse-grown plants had smaller apertures or were completely closed. Internally, hydathodes were delimited by a bundle sheath extending below the vascular tissues and approaching the adaxial epidermis on each side of the water pore zone. Files of tracheary elements extended various distances into the leaf teeth. Small, irregularly shaped parenchyma cells (epithem) abutted on the xylem parenchyma cells, filling the space between the files of tracheary elements and the adaxial epidermis. The hydathodes of plantlet leaves were smaller with fewer water pores and reduced epithem than those of greenhouse-grown plants. Ex vitro guttation probably occurs as a result of increased water potential and high relative humidity when plantlets are transferred from culture to soil.

Open Access

Abstract

Leaves of in vitro-grown plantlets and greenhouse-grown plants of ‘Totem’ strawberry (Fragaria × ananassa Duch.) were compared using scanning and light microscopy. Each apex and marginal serration of in vitro- and greenhouse-grown leaves had a terminal hydathode region. The leaf teeth were composed of an acuminate-mucronate tip, obscured in greenhouse-grown plants by an abaxial cluster of thick-walled unicellular trichomes, and a subterminal, adaxial group of sunken water pores. Water pores and stomata of plantlet leaves were open, whereas greenhouse-grown plant leaves had closed water pores and stomata or comparatively small apertures. Internally, the hydathodes of greenhouse-grown plants and cultured plantlets were delimited by a bundle sheath that extended below the vascular tissues, approaching the adaxial epidermis on each side of the zone of water pores. Between the epidermis and the vascular tissues were loosely arranged epithem cells. The hydathodes of plantlet leaves were smaller than greenhouse-grown plants, with fewer water pores and reduced epithem.

Open Access

Abstract

Foliar anatomical comparisons were made between in vitro-grown plantlets and greenhouse-grown plants of ‘Silvan’ blackberry (Rubus sp.) using scanning and light microscopy. Each apex and marginal serration of in vitro- and greenhouse-grown leaves had a terminal hydathode region composed of a scattered, primarily adaxial, group of sunken water pores. Water pores and stomata of plantlet leaves were open, while greenhouse-grown plant leaves had closed water pores and stomata or comparatively small apertures. Internally, the hydathodes of both cultured plantlets and greenhouse-grown plants were delimited by a bundle sheath that flanked the vascular tissues and extended to the epidermis. Between the vascular tissues and the epidermis were loosely arranged epithem cells. The hydathodes of plantlet leaves were simpler than those of greenhouse-grown plants, with fewer water pores and reduced epithem. Water loss from detached leaves of plantlets occurred through both leaf surfaces, although more water was lost from the abaxial surface. In contrast, foliar water loss from severed leaf blades of greenhouse-grown plants was primarily abaxial.

Open Access

The relative growth and yield performance (tuber number and fresh weight) of 13 North American and European potato cultivars were assessed at a site in the Jordanian desert near Zarqa. These cultivars included `Spunta', which has long been grown in Jordan, and `Minerva' and `Ellona', which are new to Jordan. The other 10 cultivars were selected from a population of 130 cultivars that were ranked for salinity (NaCl) tolerance, using an in vitro single-node cutting bioassay. They represented top (4), medium (4), and poor (2) performers in salinized medium, in vitro. The field performance of the 10 in vitro-ranked cultivars generally validated the in vitro rankings. `Spunta' was the worst-performing cultivar.

Free access

Abstract

‘Silvan’ blackberry (Rubus sp.) has 3 types of leaf hairs: multiseriate stalked, multicelled head colleters; thick-walled unicellular hairs; and setose hairs (multiseriate trichomes that taper from a stout base). In culture, ‘Silvan’ blackberry leaves were unifoliolate, smaller, and thinner, with less cuticle and a decreased number of trichomes compared to mature leaves of greenhouse-grown plants, which were tri- or pentafoliolate. Cultured leaves had permanently open stomata, raised guard cells, and an altered stomatal and trichome distribution compared to greenhouse-grown plant leaves. Stomatal index was unaffected, but leaf size in vitro was only 1% to 2% of greenhouse control leaf area. Leaves of shoots in multiplication medium were half as large as those of plantlets in rooting medium.

Open Access

Micropropagation and minituber production technology may enable the establishment of potato (Solanum tuberosum L.) seed tuber certification programs in arid and semiarid regions of the world and reduce dependency on expensive seed tuber imports. Therefore, we investigated possible carry-over effects of moderate salt stress on the following production cycle. The yields of seed tuber- and microtuber-derived plants of potato, cv. Norland, grown in both nonsaline and saline (NaCl) growing conditions (pretreatment), were evaluated under nonsaline or saline irrigation (0 or 60 mm NaCl) in a greenhouse trial. Pretreatment had no effect on yield; there was no apparent residual carry-over effect of salt stress of parent plants on tuber yield of seed tuber- or microtuber-derived plants. Irrigation with a 60 mm NaCl solution depressed total tuber fresh weight in both seed tuber-(43%) and microtuber-derived plants (75%), but total tuber number was increased (77% and 663%, respectively). This increase in tuber numbers has potential value in the minituber production industry.

Free access