Effects of PP333 and Exogenous ABA on Leaf Tissue Structure of Armeniaca vulgaris ‘Luntaibaixing'

[Objective] This study aimed to investigate the effects of PP333 and ex- ogenous ABA on the growth and development of Armeniaca vulgaris ＇Luntaibaixing＇ so as to provide a theoretical basis for the growth regulation of Luntaibaixing in cultivation and management. [Method} Different concentrations of PP333 and ABA were sprayed to Luntaibaixing during the rapid growth period of fresh treetops. The technology of paraffin section was used to measure the thickness of leaf, upper epidermis, lower epidermis, palisade tissue and sponge tissue. The thickness ratio of palisade tissue to sponge tissue, tightness degree of leaf tissue structure （CTR） and loose degree of leaf tissue structure （SR） were calculated and the differences in leaf tissue structure were analyzed. [Result] The thickness of leaf and palisade tissue both increased significantly after treated by PP333. At the treatment concen- tration of 1 000 mg/L, the thickness ratio of palisade tissue to sponge tissue and the value of CTR were highest, while the thickness of sponge tissue and the value of SR were lowest. The thickness of leaf and palisade tissue also increased after treated by ABA, and it increased most greatly at the ABA concentration of 60 mg/L compared with CK. At the treatment concentration of 60 rag/L, the thickness ratio of palisade tissue to sponge tissue and the value of CTR were the highest, while the thickness of sponge tissue and the value of SR were the lowest. [Conclusion] ABA and PP333 treatment increased the leaf thickness, palisade tissue thickness, pal- isade tissue to sponge tissue thickness ratio and CRT value, but reduced the sponge tissue thickness and SR value of Luntaibaixing.

Low Ca^2＋ Content and Ca^2＋/Na^＋ Ratio in Leaf Tissues Determine Salinity Tolerance in Spanish Type Groundnut （Arachis hypogeal L.）

The study was performed with seven groundnut varieties/genotypes and F1s derived from crossing in all possible combinations without reciprocal among the mentioned varieties/genotypes. The objective was to assess whether low Ca2＋ content and Ca2＋/Na＋ ratio of leaf tissue or stem tissue determine salinity tolerance in terms of economic yield （kernel yield） in groundnut. It revealed that the varieties, “Binachinabadam-6”, “Binachinabadam-5” and the F1 G2 × G3 were most tolerant based on kernel yield under 8 dS/m and 10 dS/m salinity stresses. These two tolerant varieties and the F1 also showed lower Ca2＋ and Ca2＋/Na＋ ratios in leaf tissue, which indicated lower Ca2＋ and Ca2＋/Na＋ ratio of leaf tissue determined salinity tolerance in terms of kernel yield in Spanish type groundnut. These findings could be applied in future plant breeding applications for screening salt tolerant Spanish type groundnut genotypes.

Response of Leaf Tissue Structure to PP333 in Korla Fragrant Pear

[Objective] This study was performed to explore the effect of different concentrations of PP333 on leaf tissue structure of Korla fragrant pear and to lay the foundation for the cultivation and regulation of Korla fragrant pear. [Method] The leaf tissues treated with different concentrations of PP333 were dehydrated with al- cohol, embedded in paraffin and sliced into 10-μm slices. The thicknesses of leaf blade, upper epidermis, lower epidermis, palisade tissue and sponge tissue were measured, and the ratio of palisade to spongy layer thickness, cell tightness （CT） and cell looseness （CL） were calculated. [Result] The thickness of leaf blade, the ratio of palisade to sponge layer thickness and the thickness of palisade layer were all significantly increased after treatment with PP333. Treatment with 2 500 mg/L PP333 showed no obvious effect on the thickness of leaf epidermis, but increased the thicknesses of leaf blade and palisade tissue. Leaf CL was the highest in the treatment of 1 500 mg/L PP333. [Conclusion] PP333 can increase the leaf thickness, palisade tissue thickness and CT, reduce spongy tissue thickness and CL of Korla fragrant pear. Additionally, 1 500 mg/L was the optimal concentration for the application of PP333 to improve the cold resistance of Koda fragrant pear.

Response of Leaf Tissue Structure to Exogenous ABA in Korla Fragrant Pear

To study the effects of different concentrations of Abscisic Acid(ABA) on leaf tissue structure of Korla fragrant pear and lay the foundation for the cultivation and regulation of Korla fragrant pear. Using the paraffin section method, the leaf thickness, the epidermis thickness, the palisade tissue thickness and the sponge tissue thickness were measured; palisade spongy ratio, Cell Tightness(CT) and Cell Looseness(CL) were examined after treatments with exogenous ABA. Leaf thickness, leaf palisade spongy ratio and palisade tissue thickness increased significantly after exogenous ABA treatment compared with CK, while the effect on leaf epidermis was not obvious. The leaf thickness and palisade tissue thickness increased evidently after 70 mg · LABA treatment by 24.89% and 41.10%, respectively. The tissue structures of leaves were more compact, while CL was lower after 70 and 90 mg · LABA treatments. The effects of different concentrations of exogenous ABA could increase the leaf thickness, palisade tissue thickness of Korla fragrant pear and CT, reduced the thickness of spongy tissue and CL. Among those concentrations of exogenous ABA, the effect of spraying 70 mg · Lexogenous ABA was suitable for improving cold resistance of Korla fragrant pear.

Comparison of 2-Acetyl-1-Pyrroline (2AP) in Rice Leaf at Different Growth Stages Using Gas Chromatography

Aromatic rice lines were examined for 2-Acetyl-1-Pyrroline (2AP) content in leaf tissue at five different growth stages (tillering, panicle initiation, 50% heading, booting, and maturity). A small plot trial with plot size of 1.42 m × 4.88 m (7 row-plots) was arranged in completely randomize design with three replications. Dry-seeded, delayed flood cultural practice was used in this study. The experiment was conducted at three locations. The average 2AP concentrations in leaf tissue at tillering stages were higher than the other four growth stages. 2AP levels were declined when rice plant reached booting. AP levels decreased slightly at heading stage and decreased significantly at maturity. There was no significant different between 2AP in leaf at 50% heading from three locations as well as the 2AP content in rice grain. Correlations between 2AP in leaf and 2AP in grain were significantly in all five growth stages. The highest correlation coefficient was found between 2AP in leaf at booting and grain (r = 0.811**) and lowest was in the leaf at harvest (r = 0.564**). Results indicated that 2AP could be determined in leaf tissue at early growth stage.