복숭아 네 품종 ‘오도로끼’, ‘가납암백도’, ‘진미’, ‘장호원황 도’ 신초의 저온순화 및 탈순화 동안 시기별 내한성 변화는 전해질 누출률을 분석하여 나타냈다. 또한 내한성 결정 요인 을 분석하고자 SDS-PAGE를 이용하여 dehydrin 함량 변화를 확인하였으며, 그와 관련된 유전자 발현 분석은 quantitative real-time RT-PCR을 이용하여 수행하였다. 네 품종의 내한성 은 2012년 12월까지 꾸준히 증가하였으며 그 후 2013년 4월 까지 감소하였다. PpDhn1 유전자가 인코딩하는 60kDa의 dehydrin 단백질은 탈순화기(2013년 3-4월)에 비하여 저온순화 기(2012년11월-2013년 1월) 동안 높은 축적이 확인되었다. PpDhn1 유전자와 PpDhn3 유전자 발현양상은 복숭아 네 품 종에서 내한성 변화와 평행하게 나타난 반면, PpDhn2 유전자 는 뚜렷한 시기별 패턴을 나타내지 않았다.

Hand leaf thinning for improvement of fruit coloration and quality is one of the most labor-consuming works in Korean apple cultivation. The study was aimed at investigating whether foliar application of two chelate compounds (Cu-EDTA, Fe-EDTA) could defoliate effectively ‘Hongro’/M.9 apple leaves and enhance fruit coloration and quality. At 30 days before harvest, foliar spray with two chelate compounds defoliated significantly the apple leaves. Chelate treatments did not affect the leaf chlorophyll content. High concentration of chelates decreased drastically photosynthetic rate of true leaves, and then it stayed in low levels, whereas low levels of chelates reduced sharply the photosynthetic rate but it was gradually restored over time. Cu-EDTA regardless of its concentration triggered higher defoliation compared to Fe-EDTA. Consequently, higher defoliation improved light interception of fruits and accumulated more anthocyanin. Particularly, Cu-EDTA could target mainly fruit cluster leaves which affect directly light interception of the fruits, i.e. more selective defoliants compared to Fe-EDTA. However, 3% Cu-EDTA rather defoliated excessively, accompanying with reduction of fruit weight and soluble solids. Therefore, our results suggest that 1% Cu-EDTA which defoliates properly the fruit cluster leaves could improve coloration and quality of ‘Hongro’/M.9 apple fruits.

사과 ‘후지’/M.9 포트묘목 개발을 위해 질소시비농도에 따른 생장특성을 조사하고, 포트 우량묘목 생산에 적합한 질소시비 농도와 잎의 무기영양성분 함량 및 토양 화학성의 안정성을 확인하였다. 질소시비농도가 높아질수록 묘목의 생장은 증가되 었고, 특히 16 mM 처리가 수체 생장에 가장 좋았으며, 우량묘목 판단기준에 부합하였다. 32 mM 이상의 고농도는 오히려 생장 을 감소시켰다. 잎의 무기영양성분 함량은 8, 16 mM 처리구에서 기존 사과과원의 적정수준보다 높았고, 이러한 무기영양성분은 정식 후 수체 생장에 도움이 될 것으로 생각되었다. 토양 화학성 또한 8, 16 mM 처리구에서 안정적이었다. 따라서 수체 생육, 잎의 무기영양성분, 포트 내 토양화학성을 고려한 결과, 사과 ‘후지’/M.9 우량 포트묘목 생산을 위한 적정 질소시비량은 16 mM로 판단되었다.

Effects of different soil water conditions on fruit characteristics were investigated in 5-year-old ‘Nero’ black chokeberry trees (Aronia melanocarpa). Three kinds of drought stresses, including low water deficit, severe water deficit, and very severe water deficit, due to decline of soil water decreased the fruit quality of weight of 10 berries, soluble solid content, and anthocyanin, compared with the control (consistent water supply) during the harvest period. After longer drought stress, supply of soil water could induce berry cracking because cell size of epidermis of fruits contracted, whereas cell size of sub-epidermis and flesh expanded. Thus periodic water supply using water supply facility is needed for yield and quality of ‘Nero’ black chokeberry fruits.

Proline has been shown to accumulate in plant under various type of stresses. In our previous study, changes in cold hardiness and proline content showed contrasting patterns during a constant deacclimation. This study was performed to investigate the proline accumulation and related gene expression in response to repeated deacclimation and reacclimation in peach cultivar ‘Daewol’. Proline content was analyzed using the ninhydrin method and related gene expressions were examined using quantitative real-time RT-PCR. Proline contents of ‘Daewol’ increased during the repeated deacclimation treatments. Interestingly, during the twice deacclimation, expressions of P5CS (Δ1-pyrroline-5-carboxylatesynthase) constantly decreased, whereas expressions of P5CR (Δ1-pyrroline-5-carboxylatereductase) increased. Expressions of OAT (ornithine-δ-aminotransferase) indicated up- and down- pattern in response to repeated deacclimation and reacclimation. Our results indicated that proline responds positively to higher temperature in the shoots of peach cultivar ‘Daewol’ and expressions of both P5CS and P5CR genes could show contrasting patterns during the deacclimation. Moreover, our results suggest that ornithine pathway could serve as an alternative pathway in proline synthesis process during deacclimation in peach.

Proline (Pro) accumulation is a common physiological reaction in response to abiotic stresses in many plants. Accumulation of Pro is believed to play the important role in protecting cellular components from dehydrating effects due to such stresses. The study was performed to investigate the relationship between cold hardiness and Pro content or expression of related genes in peach cultivars during a constant experimental deacclimation. Changes in cold hardiness were determined using electrolyte leakage method in the shoots of 10 peach cultivars (Prunus persica ‘Aikawanakajima’, ‘Chiyomaru’, ‘Daewol’, ‘Janghowon Hwangdo’, ‘Kiraranokiwami’, ‘Mihong’, ‘Misshong’, ‘Soomee’, ‘Suhong’, and ‘Sun Gold’). Pro content was analyzed using the ninhydrin method and related gene expressions were examined using quantitative real-time RT-PCR. While cold hardiness of 10 peach cultivars decreased, Pro contents of those increased during the deacclimation. Notably, at the same time, expression of P5CS (Δ1-pyrroline-5-carboxylatesynthase) decreased in 10 peach cultivars, whereas expressions of P5CR (Δ1-pyrroline-5-carboxylatereductase) and OAT (ornithine-δ-aminotransferase) increased. Our results demonstrate that Pro responds positively to higher temperature in the shoots of 10 peach cultivars and expression of both P5CS and P5CR genes could show contrasting patterns during the deacclimation. Furthermore, our results suggest that ornithine pathway, which has been suggested to be important during seedling development, could serve as an alternative pathway in Pro synthesis process during the deacclimation in peach.

In this study, we sought to identify primary pears species and Korean native pears, without the use of morphological characteristics. In addition, this study was to establish pear DNA fingerprinting data for Korean native pears using 12 microsatellite markers, and to accurately classify a database for management of the Korean pear collection. Forty two pear accessions (7 primary pears, 5 Asian pears, 29 Korean pears, and 2 reference pears) were analyzed with twelve primers covering whole pear genome. In the present study, all pear accessions were successfully classified along with their pedigrees, and the distribution of primary pears was parallel to those of the previous taxonomic results. Korean pears were divided into 3 groups. Group I was characterized by Pyrus calleryana, and included Korean pea pears. Group II was characterized by P. pyrifolia, and was classified into 2 small groups. The first small group comprised of ‘Najucheongbae’, ‘Sunchanggulimdolbae’, ‘Andongmookbae’, ‘Andongdangsilri’, and ‘Najucheongbae’ and was presumed to be cultivars of P. pyrifolia. The second small group consisted of ‘Cheongdangrori’ and ‘Pyeongchangsuhyangri’. These two accessions were assumed to be a hybrid of P. pyrifolia and the other cultivar. Group III was characterized by P. ussuriensis. ‘Goesanhwangbae’, ‘Andongcheongsilri’, ‘Gongjucheongsilri’, and ‘Yecheoncheongbae’ were assumed to be cultivars of P. ussuriensis. Contrary to ‘Ulreungdocheongbae A’, ‘Ulreungdocheongbae B’ was classified as belonging to the P. ussuriensis group. It is possible that this is a consequence of, P. ussuriensis genes being transferred into ‘Ulreungdocheongbae B’. The result of this research reaffirmed the efficiency of a standard set of microsatellite markers and provides data, which will be useful for developing a core collection of pears.

Changes in cold hardiness were confirmed with relative electrolyte leakage (REL) method in the shoots of two peach cultivars (Prunus persica Janghowon Hwangdo and Odoroki) during cold acclimation and deacclimation. Changes in proline (Pro) content and related gene expressions were also analyzed. Particularly, transcript accumulations of P5CS and P5CR were examined using quantitative real-time RT-PCR. REL in the shoots of two peach cultivars was significantly different during the entire experimental period. Cold hardiness of two cultivars increased gradually to December 2012, and then decreased to April 2013, whereas Pro contents of ‘Janghowon Hwangdo’ and ‘Odoroki’ were reduced from the beginning of the experiment to February 2012 and then increased in the spring. Interestingly, P5CS gene encoding an enzyme, which catalyzes conversion from glutamic acid (Glu) into glutamic-γ-semialdehyde (GSA) in the first step of Pro pathway, showed the contrasting patterns with Pro contents of two cultivars. On the other hand, P5CR gene encoding an enzyme, which catalyzes conversion from Δ1-pyrroline-5-carboxylate(P5C)intoPro in the final step of Pro pathway, showed the similar patterns to Pro contents in two cultivars. Our results demonstrate that Pro responds negatively to low temperatures in the shoot of different peach cultivars, including the supplemental 10 peach cultivars, and expression of both P5CS and P5CR genes could show contrasting patterns from each other. Our results suggest that identification of both P5CS and P5CR genes are required necessarily for accurate analysis of Pro biosynthesis because Pro accumulation is affected more by expression of P5CR gene.