S-3307和PP333对水稻秧苗促蘖效应的比较测定及其与植物内源激素关系的研究

报道了Ｓ－３３０７和ＰＰ３３３对水稻秧苗促蘖效应的比较测定及其与植物内源激素关系的研究结果：（１）用４０μｇ／ｍＬＳ－３３０７和４００μｇ／ｍＬＰＰ３３３进行浸种处理的秧苗，在三叶一心期分别有６５．０１％和１９．７９％的植株出现分蘖，对照秧苗无分蘖出现，Ｓ－３３０７和ＰＰ３３３对水稻均有促蘖效应，而前者的促蘖效应大于后者。（２）经Ｓ－３３０７和ＰＰ３３３处理的秧苗以及对照秧苗，在三叶一心期的苗体内，每克鲜重ＣＴＫ含量分别为１３４６．４，８４２．４，８６．４ｐｍｏｌ／ｇ；ＣＴＫ／ＩＡＡ的比例分别为３．６９，２．５４，０．２９。在同期测定了秧苗体内可溶性糖、淀粉和全糖以及可溶性氮、蛋白质和全氮含量，它们在三种处理苗体内无明显差异。（３）本试验结果表明：Ｓ－３３０７对水稻的促蘖效应大于ＰＰ３３３，Ｓ－３３０７和ＰＰ３３３的促蘖效应与其提高水稻秧苗体内ＣＴＫ含量和ＣＴＫ／ＩＡＡ比例密切相关，其中Ｓ－３３０７提高ＣＴＫ含量和ＣＴＫ／ＩＡＡ比例的作用大于ＰＰ３３３，这一点与Ｓ－３３０７的促蘖效应大于ＰＰ３３３的结果是相吻合的。

Relationship Between Heterosis and Endogenous Plant Hormones in Liriodendron

To investigate the possible involvement of endogenous plant hormones in heterosis of Liriodendron interspecific hybrid, growth traits and contents of endogenous GA 1/3 (gibberellin A 1, A 3), IAA (indole_3_acetic acid) and iPA (isopentenyl adenine) of tulip tree ( L. chinense (Hemsl.) Sarg.), yellow poplar ( L. tulipifera L.) and their interspecific hybrid ( L. chinense × L. tulipifera ) were examined. Results showed that: (1) the heterosis in height growth trait of the interspecific hybrid was mainly caused by the reletively greater elongation of internodes. Although the uppermost three internodes had the potential of elongation, the first one, which had the greatest elongation amount, contributed to the heterosis of the height growth trait; (2) the contents of endogenous GA 1/3 , IAA and iPA were greatly different among tulip tree, yellow poplar and their interspecific hybrid. All of the three interspecific hybrid families studied significantly contained higher amount of endogenous GA 1/3 and iPA in the uppermost first internode than their parental species. And thus, a correlation between the contents of endogenous GA 1/3 and iPA, and hybrid vigor for height growth trait in Liriodendron was observed; (3) the rankings of endogenous GA 1/3 and iPA contents in the uppermost first internode of three hybrid families studied were not similar to the ranking for height of 3_year_old trees. Therefore, the contents of endogenous GA 1/3 and iPA in the uppermost first internode could not be used in predicting hybrid vigor among hybrid families.

Effects of Exogenous Putrescine Application on Hormone Content of Citrus aurantium L. Seedling under Salt Stress

A pot experiment was conducted in lath house to study the response of six month-old seedlings of sour orange （Citrus aurantium L.） irrigated with salinity water （1, 2 or 4 ds/m） for four month. The seedling was sprayed with putrescine at 0, 150 or 300 mg/L concentrations for three times with month interval, for investigation the effects of putrrescine spraying on hormonal changes in sour orange seedlings under salt stress. One month after the last putrescine application, the leaves of the vegetative shoots were picked for endogenous plant hormone determination. The results indicate that increasing level of irrigation water salinity to 4 ds/m significantly increased ABA, Put and SA; whereas, decreasing IAA and GA in leave. Spraying vegetative canopy with putreseine at 300 mg/L increased 1AA, SA, ABA and Put, while decreased GA. It can be concluded that the adverse effects of high salinity irrigated water on endogenous plant hormone can be ameliorated, to some extent, by exogenous application of Put at 150 mg/L or 300 mg/L concentration.

Fruit Set in Orange with Phytohormones and Its Relation to Endogenous Levels of GA3

This research work aims to contribute in increasing the fruit set in citrus, given its importance in determining fruit yield. The authors evaluated the effects of phytohormones （auxins, gibberellins and cytokinins） in the mooring and features of orange fruit in cultivars Washington navel and Thomson （Citrus sinensis （L.） Osb.）, The experiment was established in a split plot randomized complete block design with five treatments and four replications. Flower tissue samples were stored in liquid N until the extraction of gibberellins and the identification and quantification of GA3. The results showed statistically significant difference （P 〈 0.05） between treatments in the number of fruits retained 129 d after flowering and the percentage of final tie. GA3 content ranged, on a dry weight basis, from 1.66 mg＇g1 in the control to 20.79 mg.g-1 in the high dose. The mean dose （32.2 mg.L-1 auxins, gibberellins 32.2 mg L-1 and 83.2 mg.L-1 cytokinins） caused the largest increase in fruit set.

Mutualistic fungal endophytes produce phytohormones and organic acids that promote japonica rice plant growth under prolonged heat stress

This study identifies the potential role in heat-stress mitigation of phytohormones and other secondary metabolites produced by the endophytic fungus Paecilomyces formosus LWL1 in japonica rice cultivar Dongjin. The japonica rice was grown in controlled chamber conditions with and without P. formosus LWL1 under no stress （NS） and prolonged heat stress （HS） conditions. Endophytic association under NS and HS conditions significantly improved plant growth attributes, such as plant height, fresh weight, dry weight, and chlorophyll content. Furthermore, P. for- mosus LWL1 protected the rice plants from HS compared with controls, indicated by the lower endogenous level of stress-signaling compounds such as abscisic acid （25.71%） and jasmonic acid （34.57%） and the increase in total protein content （18.76%-33.22%）. Such fungal endophytes may be helpful for sustainable crop production under high environmental temperatures.